Well of course, there is of course the derp face glitch, that will always be one of the greats x3 I've seen a few others though:
1) jumping off the rock near the waterfall in Ficho while dashing will place you on top of the walls (basically the wall run glitch)
2) if another user sits at the base of a tree or rock, they may appear to be lopsided to you
3) small characters sometimes appear to fall into rock ledges face first
If I repeated any, just ignore that ;3