It's that time again: massive Steam summer sale, up to 85% off major games
Not only are there cheap bundles -- the complete 2K Games pack for just £70 ($110), for example! -- but there's also a bunch of 'Today Only!' offers if you want to buy individual games.
For the next 20 hours, for example, you can buy BioShock 2 for just £10 ($15), or Counter-Strike: Source for £4.76 ($7).
There's no way of telling what will be on sale tomorrow, so keep an eye out! You can be guaranteed of some absolute steals.