The label says the important part. My party has an NPC who has cobbled together a circus, thanks to a certain slightly kleptomaniacal PC (I SWEAR, that wizard didn't EVER have that wand of polymorph). We need acts, beyond the normal crap. I mean, we've GOT the knife throwers, the high wire act, elephants... an owl bear, a mimic that would rather be fed than hunt... A minor carnival surrounding it. I'm looking for some REALLY weird stuff to throw at my GM.
You obviously need some rids and test of skills/carne games. The games should obviously be rigged, but fun. offer the traditional stuffed animals as prizes, and be very generous with them.
For rides, flying animals are great. No track involved, just lots of ariel acrobatics and some well made saddles with seatbelts. Griffin would be great for 1 or 2 passengers. Pegasus would be smart enough to not need a rider. A Roc would be big enough to carry a rider and a LOT of passengers.
An unusual idea for a 'ride' would be to get a few Rings of Feather Fall and some way to catapult people into a controlled area. For a few coppers they get to experience the ride of a lifetime. The person selling tickets gives them the ring. Someone (say a giant?) throws them towards the target. Ring kicks in and they survive the ordeal. Ring gets collected as they leave. Should be popular with kids.
Other cheap magic items could be used for amusements. Like a booth with several hats of disguise where you pay to use them for 10 minutes (and you aren't allowed to leave). It would be better if you had some way to take a picture.
If you can recruit a powerful kinetisist or bind an air elemental you could make a bouncy house. Just requires some strong canvas. Oh, and a ball pit. You don't even have to use magic for that, but fabricate would be perfect. Just make the balls out of something really light. Alchemists can produce foam? Hollow rubber balls should be possible if you can find natural rubber. Resin is also possible. If you use fabricate you don't even need the balls to last that long.