Seeing as there isnt a forum specific to Fez (that I can find) I'll post here.
There is a bug that has let my 7 yr old son get onto the leaderboard with 40 cubes in position 16,000 ish. How? I completed the game yesterday and didnt realize he was signed in on the other controller from earlier in the day, it was long ago enough that the controller had turned itself off. After I completed the game I checked leaderboard to see if any friends had got any further and noticed for the first time my 7yr old son had appeared on the leaderboard with exactly the same amount of cubes as I did (40).
He has never played the game, likes watching it, but never played and this is obviously some bug that happened with him being signed in at the same time as I was when i completed the game or perhaps when i collected a cube, unsure exactly.