I heard that if you go into the monorail, which doesn't work yet, and you stand in the middle of the circle, will give you free 1,000,000 credits. There's also a 1/128th of winning a stitch hat that way.
I heard a rumor that if you obtained ten sets of all the Dream Furniture and Pins you can get golden dream ears! What's different? They have gold sparkles!
The funny thing is Dream's month and frozen outfits were true eventually. Next rumor. If you win 2 billion pirates games Amy will personally give you a quest machine and double the amout of credits you've won from pirates in exchange for your soul :P