In term of major time-wasters I play Full Tilt Poker. Play money of course, I am stingy like that
But boy oh boy does that game waste time. I sometimes found myself playing for several hours and didn't gain all that much. Also I have been up to over a million play chips (which takes a while if u play with some sort of strategy and don't just rely on a huge luck string) and lost all, won over a mill again and lost it all again. Happened few times by now
The ultimate time-consumer out there must be Civilization though. I played it for a month or so. After I cut a date short where I would probably have gotten lucky in the end because I had to get back to finish that round, I realized what happened to me and uninstalled that evil piece of hell.
No More Turns ! (can't seem to directly embed the youtube link)
I have found sort of a "healthy" way of playing with the following games recently:
Bad Company 2
Starcraft 2
Nba 2k10 (on xbox 360, will buy 2k11 on release day, I just luuuuv basketball
)
Also Fallout New Vegas will come out later in October, I pre-ordered it and hope I won't loose my job because of it
I play Fallout 1+2 for like 4 times each. Then waited for a felt eternity and was finally, pleasantly surprised that Fallout 3 came out. Liked it, didn't love it as much as 1+2 but as a fan I couldn't stop devouring that game. For a month I pretty much didn't do anything but playing Fallout 3.... Thank god for the student life