For my 3 year old twins birthday, we had a Thomas the Tank Engine party. There were Thomas invitations, plates, napkins,party hats, party bags in which we had included among other things Thomas bubbles and a whistle, and of course thank you's sent out later. You can find these at Party City. When the guests entered the house, they boarded the tracks we made to lead them to the party.  With blue painters tape, I made tracks that went from the front door through our entry and into the kitchen and of course a small set of tracks leading off to the potty since many of the little guests and guests of honor would be needing it. I made a train crossing sign where it lead into the main party area. We used blue, red and yellow streamers all over and had Thomas's Track Side Tunes playing in the background.  For games we had pin the funnel on Peter Sam which the kids all loved and wanted to play over and over. On poster board I made a PeterSam without a funnel and then made funnels out of colored contruction paper for the kids and wrote their names on it. Another game we played was Hot Train where we sat in a circle and passed Thomas around, just like hot potato except with ours, you won when you were caught holding it when the music stopped.  We made sure each child won at least once. For the cakes, I found a great bakery which will make just about anytype of design or character and they made two standup Thomas's.  The inside of one was chocolate and the other yellow. This wowed the parents as much as the kids. All the kids had a great time, especially my two little engineers!!