A huge selection of free online games which are tons of fun can be found at
OMGPOP.
Online Pictionary (Drawmything), a sort of Pong multiplayer, Pool, a kind of Mario Cart thing and tons more.
You can set up private games, play with strangers or even play without signing up (lots of little flash reminders though that signing up is beneficial to you somehow - very annoying).
It's a great way to kill time for loads of people. I'd be up for a game of pretty much anything (especially draw my thing) if anyone is up for it.
The link above is a ref link (which supplies me with more XP and aesthetic player items) but to go ahead without it just go to
OMGPOP.com and see for yourself.
Pool is weird though, no 2 shots after a foul and you don't pick spots or stripes even if you pot them off the break. NOt the rules we used in Glasgow but still good fun.
-m0r