This site has a bunch of fantastic DIY carnival games and activities. including this simple KNOCK DOWN game. All you need are disposable cups and a cute sign!
East Coast Mommy: Carnival Games and Activities
Hopping Corn Science Activity - this would be an easy science project that even very young children could do. For the Texas Alliance for Minorities in Engineering’s Family STEM Nights.
Fine motor popcorn circus craft- maybe for Clap Your Hands circus theme
How to make a Plinko board [ "The easiest way to make a giant Plinko board for school carnivals or backyard fun. How to make a Plinko board.
Cotton Candy Kids Craft Using Puffy Paint - Sassy Dealz Cotton Candy Puffy Paint Craft for Kids - Ice Cream! Yum :) Really want fantastic ideas about arts and crafts?