Nintendo is accepting entries for its Paper Mario: Sticker Star diorama contest for one more day, and posted this how-to video, produced with iam8bit, to give you some inspiration when you're planning your paperboard tableaux. You could win a 3DS, the game, eShop gift certificates, and "paper trophies."
If you want some templates to get started, or if you obsessively collect Mario art, you can find some materials on the contest page, including some really cute printable Marios. We're considering making a diorama ourselves after looking at all this cute stuff ... not to enter the contest, of course, but just for fun.
Look for our review of Paper Mario: Sticker Star on the November 11 launch day.