Ball Toss. Would also make a great "rainy day" activity. You could even find tubs or buckets of varying sizes (like nesting bins) for more of a challenge for the older kids (Think Skee-ball).
A DIY Pumpkin Chuckin' Halloween Game - Sponsored by #CottonelleTarget at B-Inspired Mama
This site has a bunch of fantastic DIY carnival games and activities... including this bean bag toss made from $1 plastic bowls.
Noodle Racing - Easy, cheap, and bound to provide hours of fun for your child anyone!
Frog Jump Game - kids try to throw plastic frogs into lily pad cups from behind a line. Blogger found frogs after Easter by the rubber ducks.
Photo 26 of 114: Carnival / Birthday "Liam's 5th Birthday Carnival" | Catch My Party
Target golf game. Easy to make, lots of fun. You could have different slots for 1 or 2 pieces of candy and have the skinny slot be for the prizes. They keep trying until they get it in one of the slots.
Church Ministry Fair Carnival Tic-Tac-Toe Game with a shower curtain, blue tape, and frisbees
Cute idea to entertain kids at a Halloween party! Just use Expressions Masking Tape to create a pumpkin-themed game of Tic Tac Toe.