One of my favorite gaming designers would be introversion, one of there great games witch I believe would be cheap right now would be uplink. Its a kinda hacking simulator where you become apart of a hackivest group and have to hack into different company computers and gain money hacking into data servers sabotaging massive servers and even changing criminal records. Its a very good game and I have played a lot of it when board and need something to do.
Insurgency is a really good game. Played it a while back. Depends on what genre you're looking for. I love Stronghold 2. Mount and blade is another good one if you're into medieval warfare.