Jump Through Hoops
Get Hula Hoops and let the children jump through them. To add a bit of excitement
wrap red and orange ribbon around the hula hoop and pretend it is on fire! 
Ice Cream Clown
Make an Ice Cream Clown, The head is a scoop of ice cream with a ice cream cone
hat. You can then decorate the clown with M & Ms, Hot Fudge, Sprinkles,
Caramel, etc. A great tasting cute treat for your kids.
Bean Bag Toss
Draw a large clown face on a piece of poster board. Cut a hole out where the
clown's mouth would be (make it at least twice the size of the beanbag). Tape
the board to a chair and let each of your children take three tries to throw
the beanbag into the clown's mouth. 
Circus Shapes Treat
Using shaped cookie cutters make sandwiches, Jell-O, cookies, or other treat
in the shape of circus things.
Pin the Nose on the Clown
Give each child a nose (pompom with double sided tape on it) and blind fold
them and have them put the nose on the clown (you can spin the children but
it is better not to do this for younger ones)