For my son's 5th birthday we had a circus. 6 months planning in which I had more fun planning than any child had at the circus!  Off E-Bay I purchased a circus poster. I cut and paste off my comuputer so the front read "Mathew's Circus is Coming to Town".  I color photocopied the poster so the invitations looked like actual posters. The backside read "Hurry, Hurry don't be late, Mathew's Circus is sure to be great.  We'll have balloons & clowns & even a zoo, but it won't be complete unless we also have YOU!  For the party I had a petting zoo in the front yard.  Of course, there was circus music playing throughout. In the back 1 game: pin the nose on the clown. I painted one 7 foot clown so parents could play also. 2. Fishing booth - oriental trading co. has a play fishing pole, I used 2 flag poles and a blue tablecloth with fish my son made for the water.  Behind the "water" a child put prizes on the line and tugged each time a guest threw the line over. 3. Ping pong balls in fish bowls with different colored water. 4. Ring of fire - Off e-bay I purchased a poster of a tiger jumping threw a ring of fire.  I glued gold Christmas garland around a hoola hoop and attached that to a pole.  Guests had to throw a stuffed tiger through the ring.  I also had a life size tiger cutout for decoration. Circus Side Show - E-bay purchased 2 circus animal train carts.  My son made 2 mystery animals.  Guest had to guess what they were.  For background I made a poster of real side shows (non scarry).  House of Horrors - I painted a refrigerator box black on the inside and put 2 black lights inside. I purchased "blacklight bubbles" (they glow under blacklights), made pictures of silly clowns out of flouresent paper and attached to the walls, and bought flouresent pens so kids could draw on the inside of the walls themselves.  House of Fun - I filled a refrigerator box top & sides full of balloons and on the bottom had bubble wrap.  The kids crawled across & popped the bubble wrap.  Tightrope - a 2X4 covered with a checkered tablecloth. Kids wore smudged oversized clown glasses (they could not see there feet.  Finally, I had a life size baby elephant cutout and 2 circus tents (Stumps) for background for kids to get a poloroid picture taken.  I purchased clown wigs, clown shoes, had face painting, hats, red noses, etc. so guests could dress up, then get there pictures taken.  I hired a clown for magic, she lead a musical clown pirade (each child was given a noise maker) to the life size clown pinata.  The cake was a three ring circus including a carousel with different colored horses I made from sugar, in sugar molds, clown candles, etc.  Very big hit. Parting gifts included coloring books I made telling the story of how the party came to be.  On the cover it read "Clowning around at Mathew's Circus". T-shirts that read the same were my prizes for different games I held (best looking clown, etc.) The looks on the childrens faces made the effort all worth while.