Here's a glitch that I accidentally found a while ago. It works in Tracker Barrel Trek and may work on other levels (I haven't tried). At the beginning of the level, run up right to where the waterfall starts (at the end of the little slope) and switch Kongs. If you did it right, you'll fall through the floor and lose a life! Weird glitch indeed. I wonder why this happens?
Here's a video I made too:
http://www.youtube.com/watch?v=Pj0_TwOYWCI