For us in a sense the Agile is a game. We first played it against ourselves, trying to make our velocity. But recently a large team has broken up in two smaller teams and we officially don't play against each other. But we do track our progress on the same whiteboard and keep a close eye on "the other line".

Only after reading this post I realize we just gamefied our work by going our flavour of agile, and it works for us.