[reitanqild]

Consider CS, offline agains bots then, matches are clearly defined, it doesn't get personal and you can choose between 10min deathmatch, best of 15 rounds which takes about 15-20 minutes and competitive (best of 30 rounds) which takes around an hour.

Edit: basically anything I guess as long as it fools the brain into thinking there is something important going on and it isn't to addictive.