When my son turned 4, he wanted a Hot Wheels/Race Car Party. I used the free invitation from the Hot Wheels web site and glued it to red card stock. As the guests arrived, they passed the checkered flags I had lined up along the drive and walkway.  I hung two king size sheets along one wall of my garage (to hide the mess) and pinned traffic signs to them that I had made from colored posterboard (for example: No Parking, Speed Limit 25, Detour, Yield, Stop, etc.). I also hung green, red, and yellow streamers from the ceiling of the garage and along the inside of the garage door. I had two long tables set up in the garage covered with red plastic. I used streamers, curling ribbon and Hot Wheels cars on the tables for decoration. Red, yellow, and white balloons were placed in groups of three in different areas of the garage.  The first activity was making personalized license plates from craft foam.  The letters of each child's name were also cut from foam and sequins, buttons were glued on for extra decoration. (If I did this craft over again, I would use a Sharpie and write the names on the foam -- it would save a lot of time). A piece of yarn was tied through two holes in the top so they could take them home and hang them up in their room. Those were left to dry while the guests went outside for fun and games. I had decorated two large boxes to look like race cars.  The kids poked their heads through a hole in the top and we had a relay race, then played "Pin the Car on the Racetrack", and finally tossed bean bags through a "tire" I had cut out of black foam board. After games, it was time for the figure-8 race track cake I had made using two round cake pans (one chocolate, one white). I cut a hole out of the center of each one, then cut one of the circles in half and placed it on top where the two cakes come together (this made a "hill"). I frosted the cake with light green frosting and put plain M&M's around the edges of the track.  I also used graham cracker rectangles along the outer and inner wall of the cakes for support. I used race car candles and put them on the "track". I used Hot Wheels plates, and black cups, yellow napkins.  The goodie bags were black and I had cut out red, yellow and green circles from construction paper and glued them on to make it look like a traffic light. Then punched holes in the top and tied with a ribbon.  When the guests left, they got to take with them their goodie bags, a checkered flag, and a traffic sign of their choice.  It took a lot of planning and work (especially making the traffic signs), but I loved doing this party. My son and his friends talked about it for months afterwards.