You can now pre-purchase the newest entry to the Counter Strike series, Global Offensive, from Steam. Steam also takes 10% from the total price if you pre-purchase it, bringing it down to a low price of $13.49. There’s also a package that includes Counter Strike, Counter Strike: Condition Zero, Counter Strike: Source, and Counter Strike: Global Offensive, all for $18.96 (as opposed to $54.96, when bought separately).
More about the game (from the Steam page):
Counter-Strike: Global Offensive (CS: GO) will expand upon the team-based action gameplay that it pioneered when it was launched 12 years ago.
CS: GO features new maps, characters, and weapons and delivers updated versions of the classic CS content (de_dust, etc.). In addition, CS: GO will introduce new gameplay modes, matchmaking, leader boards, and more.