For my son, Jacob's 4th birthday he wanted a Thomas the Tank Engine Theme. For the invitations I made a tri-fold brochure with Thomas on the front, James on the second page and Henry on the third. They said "All aboard for Jacob's 4th Birthday Party!" They included boarding time and gate and departure time. Also a RSVP to the station master (me). I also included boarding passing which had the time that Thomas was arriving and all the activites that would be had. (I hired a clown-type guy, who dressed as Thomas and played games and painted the kids faces). I gathered large boxes from work and painted each one to look like a different engine from the THomas series. I attached straps and cut out the tops and bottoms, so that the kids could "ride" in them. THey were a big hit. I made a train cake, out of three loafs cakes and decorated them to look like THomas, Annie and CLaribel. I also made a bunt cake and put chocolate frosting on it, so that it looked like a mountain and I placed my son's Edward, James and Henry train around it on a track that was made out of frosting. I put up posters that I got out of his Thomas magazine and I bought thomas and friends decorations. The moon bouncer was a big red "Bertie the bus". I also had his THomas music cd playing in the background. This was one of his favortie parties and probably the one I had most fun planning!