If you have been purchasing Indie bundles you proabably already have some of these games. But if not, it may be worth purchasing.
Contents: Killing Floor + All DLCs, Commie Orchestra 1 & 2, Dwarfs, the Ball, and Rising Storm.
An unrelated title you might want to check out is The Stellar Impact Bundle, a multiplayer space naval battles game, $3 now (75% off). http://store.steampowered.com/sub/14131?snr=1_8_4__501
Killing Floor DLC floods the Steam store, so damn annoying. There's a million of em :/