Playing S.T.A.L.K.E.R.: Call of Pripyat, and a tad of Avencast and Disciples 2.
Stalker is awesome, I liked the first game and this one is even better. In stalker you play the role of a 'stalker', and no, you aren't a sex-offender. A stalker is something along the lines of a treasure hunter mixed with a gunman mixed with several other ridiculous occupations. You go into 'the zone' which consists of an alternate-reality Chernobyl in which the radiation completely took over and mutants are everywhere.
The idea is that these mutated things, I really can't explain what they are, that have strange unusual powers are called artifacts and once people found out about them and how much scientists want to study them or more precisely how much they're willing to pay to study them it attracted a lot of people even though death is rather common in the zone.
You fight mutants, other stalkers and come across anomalies which are OTHER strange mutated things that are rather unexplainable but have one consistency in that they tend to make you dead. It's a difficult, but fun game.
My favorite feature about Call of Pripyat is that you can upgrade weapons and armor and repair them, which you couldn't do in the first game (I ended up trashing a looot of gear). The upgrades are picked in a tree, somewhat like skill trees and thus there is actually some choice instead of a basic +1 upgrade.
I'd go into the other games but this post is already ridiculously long.