Animal Crossing: City Folk Glitches

The Bunker/Cooper Glitch
While in the the "gate" area of your town, with Cooper and Bunker, you can actually get squeezed in between them and the wall! You'll need two players while on wifi to do this glitch.

To get in that small crack, you must both crash into it. Both coming from slightly different angles. Eventually, one of you will be pushed right next to Bunker/Cooper, almost inside of them. It'll take a few tries, but you'll soon be able to get it really easy.