I was playtesting the My Little Pony LARP the other day with my gaming group and it didn't go as well as I had hoped.
Grazing and cantering was fine (and the write-up in the revised rulebook is excellent, if you ask me) but combat doesn't seem to work well. We tried the classic "rock-paper-scissors" approach and found it lacking because "real" ponies wouldn't be able to make that scissors gesture with their hooves, so we switched to the classic 2d12 system from the 2E Revised SMG(TM) (StableMaster's Guide), but it still doesn't have the same feel as the cartoon.
To top it all off, when the vampires attacked our ponies we discovered that there simply are no rules for Turning Undead in the rulebook. I mean, did the game designers even try this game out?