We use the expression to clown around when we talk about someone playing tricks and making jokes.
VOA: special.2009.01.11
While I was getting my face painted, I remember my mom, dressed as a clown, running around through the event to make sure it was perfect for all the families and children that attended.
Another addition to the jockey wardrobe at White Turf is an oversized pair of fleecy slippers which would look less out of place on a circus clown -- vital footwear to cover riding boots while hanging around on a frozen lake before the race.