you laugh, but I do my kegels (however you spell it) on the way to work and on the way home. It may be TMI, but i've been doing that for close to a year and don't feel like I have to worry about an "accident" if I drink too much water...lol
If you're not driving you can chair dance to the music on the radio, flex and point your toes, do those isometrics mentioned above, just tightening your stomach muscles every so often helps.