This is one I haven't heard before...I imagine it was shared on the Golden Road board, but I wasn't able to turn up anything from a quick search here.
In yesterday's (excellent) Now I Know email newsletter from Dan Lewis, he told the story of a July 2008 taping of TPiR where the contestant played a rigged game of Plinko with a great outcome.
Unfortunately, I don't see a way to link to his telling of the story, other than copy/pasting the whole text here, which could be problematic.
Here is the
Reddit thread referenced in the newsletter, which is the first-hand account. A good read if you had not heard this before.
I'd be interested in seeing the version of this game that made it to air if anyone had that episode handy.