Mongoose glitch

With the mongoose glitch, you can use it to get outside map boundaries easily.

In Forge mode on any level, grab a Mongoose and take it close to an invisible barrier. Have someone get on and then a second person get on passenger. Have the driver get off but the passenger stay on. Have another person go into Forge mode, pick up the Mongoose and by using Right and the Left stick, push the Mongoose outside of the map. The passenger can then get off, and he will be outside of the map. As one of the simpler methods to get outside a map, it is the most common means of exploration outside the invisible boundaries.

Note that you can not explore everywhere for there are still the Kill Barriers which are either done by touching the kill barrier or out of the invisible barrier for a certain amount of time.