Best April Fools Day pranks

[AerynWalker]

So it's almost April fools day and I'm feeling really uninspired this year on the pranks front. I need to give my new housemate a proper introduction to living with me with a really good prank.

Got any good stories, played any good pranks? Got any plans to mess with your irritating coworkers, your spouses or friends?

Let the group scheming begin!