Titan, you're the man... I play O8 and NLHE at the same time (I don't find it too hard a jump - I'm sure draw or stud would prove harder to mix with Holdem or Omaha).
Generally, though, I try to only have one proper cash game going at any one time - whether it's a Sit-n-Go or a ring game or whatever, and any others will be freerolls
. If it gets interesting on the main game I'll just put the others on post and fold, and come back when there's a lull. Sometimes I've signed up for a few SnGs and 2 or 3 start close together, and I don't get a chance to unregister, so I play multiple real money
games at once... on a 1600x1200 display it's not too bad, but on the laptop with only 1024x768 you only really get one table in view at once, and when 3 hands come up at once it can be hard to switch between them without getting slightly lost...
If you're playing a psychological game, then you probably need something like PokerOffice to give you plenty of accurate information on the other players. A solid maths-based game suffers rather less from playing multiple tables, as reads aren't the basis of your strategy.
One of the other things I'll sometimes do to pass the time is just watch a couple of other tables - see if I can spot players at multiple tables, see what the other tables at the same stakes are like (whether they look more profitable), or to see how the higher-stakes games look compared to the ones I'm currently bankrolled for... the fringe benefits of the last one being it motivating you to build up your bankroll and to make putting your money in seem less scary after watching 3- and 4-figure pots regularly between