A circus theme would be cute! I always like the kids' names to be on the door in some fashion. I would put a Ringmaster near the top, with your name on her. Then have different clowns, animals, tight rope walkers, etc... all over the door. When you get your kids' names, you can add them to the pictures. You can probably get a circus coloring book to find different circus pictures - or use several shaped tablets (school supply stores). Or even a bulletin board set may have enough cut-outs to label.
Sorry, my mind's blank on anything else right now. You might want to start a new thread called "Circus theme" and see what others can recommend.