My son celebrated his 3rd birthday in Bob style. He loved Bob The Builder and so we went all out.  We sent out Bob invitations and encouraged all guests to dress like Bob or Wendy! We rented a hall to accomodate our family and friends, over 50 people in all. All of the tables were decorated in bold colors with a plastic hard hat in the middle for a centerpiece.  I cut a hole in the top of the hard hats and strung helium balloons through them.  We had a long head head table set up for all the children.  Each child's place setting included Bob party favors and a hard hat to wear.  There was a balloon tied to each chair for the child to take home at the end of the evening.  The evening started with two games that the 3 year olds all enjoyed.  I drew a large Bob The Builder, minus his hard hat, on poster board.  Each guest was given a yellow hard hat cut from construction paper to pin on Bob's head. We covered the child's eyes and they all got a laugh out of where the hat ended up.  The second game consisted of throwing bean bags into the back of a waiting toy dump truck.  After the children played each game, they got to head over to a real tool box to pick their prize.  After the games the kids settled at the table for cake.  We had a Bob The Builder shaped cake and everyone was more than ready when I called "Dig in"! I also made cupcakes and decorated them with Bob sugar candies. When we had finished with cake, out came the Bob pinata.  Since the children were small, we went with the pull string pinata. It was a real hit. The children filled their treat bags with fun toys and sweet treats from the pinata. During the clean up process, we stuck in a Bob video and that relaxed the children and kept them quiet while the adults cleaned up the hall.  It was fun for everyone and my son has wonderful memories.