For our son's third birthday party we had a dinosaur theme party.  For the invitations I took 2 sheets of white paper and cut out the shape of an egg. I cut the top of the egg with zigzag scissors and glued the edges together to form a pocket. I printed all the information on a dinosaur shaped piece of paper that I then put into the egg.  The invitations read: The Dinosaurs are back for a prehistoric Birthday bash. Place: Our cave Time: RSVP Please don't be extinct! For hats I took poster board and made 2 side views of a dinosaur head.  I glued the noses together and then put elastic on the back to hold them on.  I also took green poster board and made some huge dinosaur feet with white claws for the children to put over their shoes.  For activities we had a dinosaur egg hunt.  I mixed cornstarch, water and sand on the stove until it became a putty consistency. I then shaped it into egg shapes around little plastic dinosaurs. After the kids found them we put them in ziplocks and smashed them open to get the dinosaur. The biggest hit of the day was the dinosaur bone hunt.  I took a huge plastic container and filled it with popcorn. I baked some sugar cookies that I cut out with dog bone shaped cutters.  We put several dozen cookies in the popped popcorn and let the kids dig for dinosaur bones. They kept putting the bones back in to look for them again.  I made a tyrannosaurus and a triceratops cake for the kids.  To save time before the party I put scoops of ice cream in paper muffin liners and topped them with candy sprinkles.  I used my son's dinosaur printed sheets as tablecloths and put all of his plastic dinosaurs around to carry out the theme. I also used the sand, cornstarch, water concoction to make a volcano.  I put it on a large cookie sheet and decorated around it with plastic dinosaurs and plastic trees.  I filled the volcano cavity with baking soda (test to make sure it is very fresh and active by practicing with the vinegar before the party) and poured some red dyed vinegar over the baking soda.  The kids went nuts for this.  We also had dinosaur dunking, a game of basketball.  We did a bone drop where the kids dropped doggie bones into a jar.  If I were doing this again I would use the bone shaped cookies since several of the kids kept trying to eat the milk bones. For treats the kids took home dinosaur theme coloring pages, a few small plastic dinosaurs, their hat and feet and bone shaped cookies. The kids had a blast. This was 5 months ago and the kids in my sons preschool class still talk to me about the party.