A Price is Right contestant once had a perfect Plinko game because the producers forgot to un-rig the game beforehand!
If you've ever seen The Price is Right, you probably know what Plink is. For those who don't know, let me explain. Plink is a large vertical board with a bunch of pegs placed all over the board. Players climb to the top of the board and drop giant chips down the board. These chips make their way down where they fall in spaces with dollar prices marked on them, Players win a number of chips that they can drop down and the sum of those chips is what they take home.
On July 22, 2008, a contestant was playing the game with 5 chips. Chips 1, 2 and 3 had all fallen into the largest possible money bucket, $10,000! This wasn't luck, the game had been rigged for that result. The shows' producers had filmed some commercials beforehand, and had rigged the game so that they could film a perfect Plinko chip drop.
When they realized this, they stopped filming, and made the contestant start all over! Don't feel too bad though, the show let the contestant keep the $30,000 he'd already won AND the money he made from the 5 drops that actually made it on air.