Best April Fool's tech prank: Super Pii Pii Brothers

Wii + Pee + whack-a-mole = Super Pii Pii Brothers! ThinkGeek says, "Sounds easy eh? Well the toilets open and close whack-a-mole style and occasionally the stray cat or other cute critter pops up. Spray a cat for extra points. Get too much pee on the ground and your game is over. With realistic fluid dynamics for the pee and over 100 different bathrooms from bars and palaces to automatic Japanese style toilets you'll be entertained for hours. And wait until your friends see the multi-player mode with dueling pee streams..."


Given Japan's frequently strange products, this is actually fairly believable, despite it being an April Fool's joke. I bet some Japanese company will come along and actually make the game now.
April fools runner up (because it had me fooled for a second): Geeks.com's retinal scanner (no website, sorry, it was in their newsletter):





Google's April Fool's joke this time around was pretty lame. "Virgle: the adventure of many lifetimes", a Mars colony, is being established because we evil humans have filled every "nook, cranny, and subdivision" of earth, while "raising skyscrapers and atmospheric CO2 levels." (Apparently so much so that the earth is completely uninhabitable [gasp!]) Sorry Google, but the environmentalist nutjobbery kind of diminished the humor.