So I was told to suggest this as a possible event because why not.
There is a game by Valve called DotA 2 which is currently in beta. For those of you familiar with the game Warcraft 3, DotA (Defense of the Ancients) was a mod for Warcraft 3. DotA 2 is Valve's recreation / update of the game and is available on Steam for those of you with access to the beta. If you don't have beta access, just ask me (PM / VM / Showdown Server) and I can get you an invite seeing as I have about 30.
Anyway, we can organize some DotA 2 type event. My suggestions for a DotA 2 event include a game called Pudge Wars. A hero named Pudge uses a meat hook in order to pull enemies toward him, and then proceeds to eat them dealing a bunch of damage. A gametype was added to DotA 2 that allows the same hero to be picked multiple times, and therefore Pudge Wars are available. Everyone picks pudge and you battle it out at middle lane until two towers are taken on either side. It's actually a lot of fun.
Alternatively, if we can for sure get at least 10 people online at the same time, we could play a custom game 5v5. It's just a normal dota match except it'll be 100% friendly since the stats from the game don't count. I highly advise against playing an actual 5 man stack match online since it could lead to friends fighting (even if temporary, it's never a fun time).
So, let me know what you think. Take a look at some videos of the game if you're not familiar with it. It's quite fun. :]