They are things to do when you're supposed to be writing. When I'm suffering with writer's block, I turn to housework, turn on the TV...
My favourite time-wasters are Animal Crossing and Webkinz. (Having kids will get you hooked on the weirdest things.) Those cute cartoon characters are so glad to see me and so easy to please. (Well, some of the critters in Animal Crossing aren't easy to please but they are easy to ignore.)
Housework is less fun but it does give you that warm glow of having accomplished something. So what if you now have to work until midnight in order to meet a deadline, the laundry is caught up and and those odd sticky patches on the kitchen floor are gone.
However, the most effective way to procrastinate is to write a blog about writer's block.