Kids bored enough to watch paint dry? How about watching a snail race instead? The Thingamababy blog has written up a guide to snail racing (concentric circles drawn on posterboard, or drawn with chalk on the footpath or porch if you want to race outdoors). It even provides a PDF of downloadable (tiny!) racing numbers for your snails.
A cute activity which you can use to teach kids a bit about snails and how cool they are - hopefully before they're old enough to get squicked by the snail trail - which, Thingamababy reminds us "is just a lubricant that helps them move around".
Gentemen, start your... snails!