I just had a halloween party for seven 4 year olds and all the activities were a hit. They were mostly girls but everyone enjoyed them. They are all transfereable to "cars" theme
1)Bingo - I made bingo cards with Halloween stickers (cars stickers). No one had played before so it was fun as a new game. I gave treats for the first bingo for each child but we ended up playing till all the boards were full.
2)Pin the nose on the pumpkin - My daughter painted the pumpkin and cut out the different shapes for the noses so she could practice her scissor skills and be a part of it.
3)coloring sheets as they arrived so that it didnt matter when they started and they could all join in at any time. One was even a maze (it was a little too difficult for some) I found these on line.
4) Read a ghost story - they loved it. Even the boys
5)free time to go play with my daughters toys and play in her bedroom.
6)Bowl full of jello and cool whip with fun toys hidden inside. The kids had to stick their hands in there and goosh them around till they found the eyeballs (grapes), plastic bats, skulls, etc. Make sure you put tablecloth on the table and on the floor and do it close to the bathroom so they can wash their hands off without carrying the mess around the house.
These activities filled up 2 hours of fun.
Get the parents involved too in helping!