In Banjo-Kazooie: Nuts & Bolts, there is a somewhat useful glitch that is performed in Nutty Acres. Break the top off of any tree, and get it into an open space. Get high enough for suicide and try to land on the side of it, and if performed correctly Banjo will become 'undead'. This glitch allows you to stay underwater for as long as you'd like, but if you get hurt, you'll regain your health and you'll have to do it again.
Explanation: When you hit the side of the tree, it is hard enough to render death, yet you slip off a split second after impact, so the game doesn't have time to launch the "Regain Health" sequence. That results in the health meter not filling back up. This allows you to stay underwater as long as you like. But getting hurt truly empties the meter, so the game goes through the "Regain Health" sequence.