Blacklight: Tango Down is getting a permanent price drop on Xbox Live Arcade, bringing the price from 1200 
to 800 . We reviewed the game last year and weren't very impressed with the 4 player online co-op title, scoring it a 2 out of 5 for its co-op. Jim reviewed the game stating it "left me wanting in the co-op department." Still if you are looking for a solid versus shooter that has a splash of co-op, Tango Down might be for you.
On the PC side of things, the game is on sale this weekend for only $2.50 - which is a bit more managable I think. Head over here to snag the deal from the Games for Windows Live Marketplace.