My favourite ThinkGeek "joke becomes reality" April Fool's is the
Canned Unicorn Meat.
They actually got a for-serious
cease and desist letter from the National Pork Board for that. And then they eventually made it into a real product.
Possibly the entire kerfuffle provided inspiration for this year's
Angry Birds Pork Rinds?
ETA: Archive of
past ThinkGeek April Fools. I kind of want those Tribbles 'n' Bits. And a Monolith (in)Action Figure.