Special events change something about the current round. Each round has a fair chance of featuring one, which will only last for one round. If this happens, it will be announced along with the normal round information (that you can request with "!rand").
There are many variants of special event, some as simple as a limitation in which weapons are available or a score penalty for using shoves/m2s. Some are elaborate, seriously changing the meta-game, such as an encumbrance system which penalizes you for carrying a lot of stuff by making you slower, or a designated 'baby' that takes more damage and needs to be protected by the other survivors.
The idea behind Special Events is that most game-changing things are best enjoyed in small doses. Each event is bound to be enjoyable and introduce sweet variation, but playing an entire game with the event's changes or mechanics would likely get boring or annoying. Not every round has one, though, and the large amount of different events should guarantee that none will be overplayed.
If you have a great idea for a special event that is not in Random yet, feel free to contact me about it; future versions of Random are likely to feature new special events...
Special Event List
1. Item Redundancy
One kind of item, randomly picked, will be very common this round. This could be any type of item, whether it is useful or not.
2. Rush Hour
There are a lot more common around and hordes are very large. There will be slower SI spawns to compensate.
3. Common Holiday
There are very few common around and hordes are very small. There will be faster SI spawns to compensate (about 8s), shifting the focus towards special infected action.
4. Freakshow
There are a lot of uncommon infected around. There will be fewer common and uncommon infected around to compensate.
5. Circus
Clowns. Are. Everywhere. I hope you like clowns. There will be fewer common infected (and other uncommons) around to compensate.
6. Sorry, We're Closed
Many of the doors on this map are locked. A locked door can only be opened by destroying it, which can be done with melee weapons or explosives. You can also let infected break open the doors for you.
7. Quadtastic
There will be no spitters or boomers this round. Every attack is a potential quadcap. There will be fewer common and slightly slower SI spawns to compensate.
8. Bad Weather Day
There's a spot of stormy weather this round, like in Hard Rain but more so.
9. Fog of War
There's heavy fog. To make it worse, survivors don't have outlines this round.
10. Land of Plenty
There are a lot of items lying around this map. There will be slightly more common and faster SI spawns to compensate.
11. Marksmen
The only primary weapons available this round are CS:S snipers: Scout and AWP. Survivors start with Scouts.
12. It's Christmas
There are many random gifts around.
13. Sudden Death
Survivors start black and white and will die immediately if they are incapacitated. There are no medkits. There are, however, a lot of defibs around.
Defibrillators still bring you back in black and white mode.
The defib penalty is lowered to 15 points this round.
14. Adrenaline Rush
Survivors start bleeding out as soon as they leave the saferoom. They bleed out a bit faster than normally and there are no medkits to stop the bleeding. There aren't even pills – the only health items available are adrenaline shots (maybe a rare defib).
15. No Heads-Up
Survivors have no heads-up display (mainly the health bars on the bottom of the screen). Health and items can still be seen by opening the scores — but using the scoreboard blinds you...
16. Old School
L4D1-mode this round! Only L4D1 inventory items appear and only L4D1 special infected spawn.
17. Friendly Fire
Survivor friendly fire does triple the damage it normally does in versus games. (This is close to the Hard campaign level of FF.) Careful with those shotguns!
18. Hush
This event has two versions:
1. All survivors become mute. They never utter or otherwise make any sound.
2. All special infected become silent. Survivors had better keep their eyes open... There will be slightly slower SI spawns to compensate. Tanks do make sound as normal.
19. Pickup Penalty
Every time a survivor picks up any useful inventory item (pills, weapons, throwables, etc), their team loses 5 points. Type "!bonus" to see the current total penalty.
20. Health Penalty
Every time a survivor uses a health item (pills, adrenaline, medkits and defibs), their team loses 20 points. Type "!bonus" to see the current total penalty.
21. Shove Penalty
Every time a survivor shoves (m2's) a special infected, their team loses 10 points. Only shovable capping infected count (jockey, hunter, smoker), there are no penalties for shoving boomers or spitters. Type "!bonus" to see the current total penalty.
22. Time Penalty
With every passing minute the survivors lose 25 points. Type "!bonus" to see the current total penalty. The penalty timer is paused when tanks are in play.
23. Mini-Tanks
Many tanks will spawn this map. Luckily for the survivors, they have have very low health (1500) and do less damage.
Mini-tanks are not as powerful as fully grown tanks, so their punched cars (etc) only do 25 damage. Their punches and rocks do 20 damage. They lose
rage very quickly too.
24. Keymaster
A randomly assigned survivor is the 'keymaster', only they can use doors normally. Doors can still be broken with the usual tools. The keymaster has a light over his head, so he can be easily identified.
25. Bad Combo
All survivors start with a grenade launcher and a chainsaw. If they want any other weapon, they will have to find it somewhere further on in the map.
26. Babysitting
One randomly assigned survivor is the 'baby', twice as vulnerable to all infected attacks. The other survivors are more resilient, but will have to protect the baby. The baby wears a teddybear on his head, so he can be easily identified.
27. Encumbered
The more stuff survivors carry, the slower they are. Best to travel light! Remember that you can always drop your active weapon/item with "!drop" (or sm_drop in console).
28. Booby Traps
Randomly selected items and doors are booby trapped and may explode when touched. (Not necessarily equal between teams.)
29. Skeet Shoot
There's a lot of hunters around. Survivors get 15 bonus points for skeeting them with shotguns or sniper headshots.
Only full skeets (150+ damage in a single leap) count, but team skeets give bonus too.
Hunter pounce damage is increased to 50 maximum, so keep an eye on the sky.
30. Firepower
No tier-1 weapons are available, only tier-2 and stronger. There will be more common infected and faster SI spawns to compensate.
31. Ammo Shortage
There's no ammo piles and weapons have very little ammo in them on pickup. Luckily, your team has a special ammo pack that can be deployed as an ammo pile. Hold the USE key to repack the pile as a carryable pack again. Be careful not to lose it, as you only get one for the whole round.
32. Axe Effect; Rockstars; Wifebeaters
In these events there are only women around, who come in big hordes at the irresistable (mostly male) survivors. Survivors only have their melee weapon (Axe Effect: a fireaxe, Rockstars: a guitar, Wifebeaters: any) to fight them off.
The only special infected are female boomers and spitters.
The game works very differently on this round: it is all about getting and avoiding melee attacks!
Boomers and spitters are as fast as survivors and their scratches do 8 damage. Spitters die after spitting once.
Boomers cannot vomit, but will instead be able to boom survivors by scratching them.
Witches may spawn for this round, but they only do 25 damage per slash and die to 2 melee swings.
33. Magic Gun Swap
There are no weapons or ammo piles anywhere on the map. Instead, each survivor is randomly handed a weapon with one clip's worth of ammo. When they empty their clip, they get handed a fresh weapon with one clip of ammo, and so on. You are more likely to get tier-1 than tier-2 weapons. There are no tier-3 weapons.
34. Witch Hunt
Homage to the Witch Party config. Many witches will spawn all over the place – a fresh one will spawn every 30 seconds (no witches will spawn while any survivor is in a saferoom). Survivors get 25 points bounty for each one they kill, if the witch does not get to slash any survivor. The witches do only 50 damage per slash, but are otherwise unaltered. The map is only worth half of its normal distance points.
35. Lousy Gifts
Santa's brought the coal: there are a lot of random gifts on the map, but they're all guaranteed to have negative effects when unwrapped. Survivors get 15 bonus points for each gift they open anyway.
36. MEDIC!
A randomly assigned survivor is the 'medic'. The medic has a limited supply of pills and first aid kits he can hand out. Whenever he uses or hands out a medkit or some pills, they are replaced until the supply runs out. How many items a medic can hand out depends on the estimated difficulty for the round. The medic has his own hat, so he can be easily identified.
37. Boomer Flu
One survivor has a bad case of "boomer flu". He will cough, burp and regularly have to vomit. Anyone he vomits on (survivors, special infected and common infected) will be covered with boomer bile, with all its usual consequences. The sick survivor has a boomer head over his head, so he can be easily identified.
38. Haunted Doors
Doors on this map cannot be operated or destroyed by either infected or survivors. They will open and close by themselves, at random times.
39. Directed by Michael Bay
Ever seen a movie by M. Bay? Think explosions! Big. Explosions. And a lot of them. In this round you get to experience what being in a Bay-directed movie would be like...
40. Bunnyhop Professionals
Automatic bunnyhops are enabled for this round. Hold down your JUMP key and you will automatically have perfect bunnyhop timing. Everyone hops, so beware of those tanks!
Difficulty
Many of the special events make things harder for survivors, while some make it easier. To balance things out somewhat, common horde and special infected spawn timers are adjusted for events that would be too hard or too easy with Random's default settings. The amount of items likely to be present on a map is also affected to some degree.