Crazy things you've seen your horse do?

When I got my first horse my family and I didn't have property yet to keep the horse on so we held her at a boarding facility for horses, where they had quite a bit of property and trainers available for hire, along with contests.

The important part of this story is the fact that we held the horses in separate pens, and there was a lot of other horses here.

Well, my horse being the smart girl she was found out how to unlock the pen with her mouth, and was able to get out whenever she wanted. Apparently she got bored being the only horse out though... So she started opening the other horses pens.

It was the funniest yet strangest moment when I got a called from the owner of the property asking if I could come down as quickly as possible, because she needed me to get my horse and help her get the other 15 my horse let out as well.

Anyone else have their horse do this? Or seen your horse do something funny/strange?