Mario Kart Wii
Avoid Blue Shells
On any track with a DK cannon, while flying in the air the blue shell will chase you then will fall behind. You will hear an explosion, but you will be unharmed.
Set Blue Shell
When you are on the final lap of the Delfino course in the Banana Cup, a Blue Shell will hit you on the bridge. This also happens when you are near the finish line, and also occurs almost every time you play this course, making the Blue Shell "set" to hit you.
Use same character more than once at a time
This glitch works off the fact that you are automatically placed onto the character that you were last selected on. To do it, have one person select the character so it says "OK", then have them deselect and move. Then have the another person (up to all three other people, in turn) who wants the same character select so that it reads "OK". Then, have controller one go back to the previous screen and once going back to the character selection screen, everyone who selected that character will be piled on the same one.
Strategy guides from GameFAQs