Off topic, Dwarf Fortress isn't a video game ;-)..
Dwarf Fortress is slow suicide.
I'm regularly on BF3, occasionally on D3 and have just started playing through the new Penny Arcade game "On the rain slick precipice of darkness" episode 3.
Gonna play through me3 again with the new ending DLC, see how that works out.
Used to run scams/grief in eve, which, I highly recommend. Hilarious amounts of fun destroying 3-4 years of someone else's work(huge ships, player run stations, etc), starting wars, using mild market know-how to basically tip the scales of ongoing battles(why yes, we will be buying all the ammo in your allied stations, etc)
Player run economy, players create almost everything, etc etc.