I once hit a dude so hard with a warhammer that his head glitched into a door. I kept opening and closing it and his body just flapped about. I've also seemingly knocked people unconscious: when I shout an important quest character down a hill so they get a lot of fall damage, they do not get back up again but I can still see their health bar and the enemy marker on my compass. It's really quite strange.
I don't know about weird but the funniest/most annoying glitch I've come across was when I hit Dexion with Marked for Death before turning him into a thrall. He was eternally hostile toward me and all of clan Volkihar. Everytime I entered the castle, everyone was beating his a**. Because he was essential, he would eventually get back up and they'd beat him to a pulp again. It was very difficult to interact with anyone but I laughed everytime.
Iv'e done that a millon times! like last night i was playing and i knocked my own Shield-Brother ( Farkas) down a hill, and half his body went though a tree, and his legs flaped around like crazy!....
also when Skojor died trying to fight the Sliver Hand when i found him half his body from the waist down was missing? WHAT?????