"Corrupt a Wish" is a little forum game that allows you to become a genie. Kind of.
One person makes a wish. The next poster must grant it, but also must add a consequence (relative to the wish) because genies are jerks like that. Then
he or she gets to make a wish and someone else grants and corrupts it and so on.
For example:
Wisher: I wish I never had to brush my teeth again!
Genie: Granted! All of your teeth have fallen out!
*insert wish here*
This
film also has some nice examples.
I'll go first.
I wish I could fly!