While I do not know the origin of these three codes, they are floating around the web today. Two of them unlock coins and the other a free body item.
They are: mmcode11 for 500 coins
mmcode12 for the Red Rocker T Shirt
mmcode13 for 2500 coins
Other coin codes are Pumpkin1, D23EXP11, Freehood, DECNLR10, JUNNLR11, and JULNLR11. Enjoy!