Aren't the geldings just the silliest ever?!?! My 2 boys play around like that all the time. Except I can never get great pictures like your pictures...they quit when they see me and get that look...."what?" "we werent' doing anything!" and go back to grazing.
I think those last 2 pictures of your's are adorable that's pretty cute that he reared so high he ended up sitting down and rolling over!!!