The last game I played was Titan Quest: Immortal Throne. It's my favorite hack-and-slash; I could wander around for hours just admiring the graphics and the cool item drops. Since I haven't gotten around to buying working versions of Pharaoh/Cleopatra or Immortal Cities: Children of the Nile online yet (my disks won't load on Windows 7, sadly, even in compatibility mode), it's my go-to timekiller. (I have Dragon Age: Origins waiting to be installed, too, but so far haven't found the time.)
Yeah, I'm behind the times, but "old" doesn't mean "not fun."
On my tablet, I've been poking at Dragon Realms (which is being renamed, apparently) and Random Factor Mahjongg. Nice little timekillers, and both free. (DR wants me to buy extras, but I can still poke along without shelling out actual money.)