Doom

A really excellent game, I found here:

http://www.reloaded.org/download/Doom-Roguelike/117/

the Doom roguelike. Perfect for playing, when you don't have time for excessive Adom sessions, since death comes much faster (choose proper difficulty setting ;) )

I was really into DoomRL when it came out a few years ago, but lost interest after a while. Recently, though, I've discovered the challenge modes in the new versions and have been hooked on those. I finally completed Angel of Marksmanship not too long ago, and after a string of unsuccessful Angel of Berserk attempts, I'm trying to complete Angel of Impatience.