My daughter wanted a dinosaur party for her 5th birthday and I wanted to do something different and fun. Since we had the party outside, we decorated with green and orange balloons and a green tablecloth. We had a dinosaur "nest" that was just a small sandbox in the yard where we put dinosaurs eggs and marked it with a painted cardboard sign.  We also had an archaelogical dig site marked with a painted sign.  I found a recipe for making dinosaur eggs from dirt and flour and we put little dinosaurs inside (purchased at the dollar store) and let them dry for a few days. That was the first activity, the kids got to break open their own dinosaur eggs.  (we used hammers and had a grown up supervise that activity).  Then I made dinosaur bones out of salt dough.  Just rolled out long pieces for ribs and the spine I rolled out a long piece and then pinched it in every 1/2in or so.  I made a flat circle for the skull and then used a butter knife to cut an eye and the mouth. I made one brontosaurus with no teeth and a T-rex that I made triangle teeth for and put them in the mouth. Then after I had cooked them, I buried them in the yard with just a light covering of dirt and marked the "dig site" with a cardboard sign. I let the kids use old paint brushes to uncover the fossils. (dried salt dough lookes very authentic when you get it a little dirty) Then we had a dinosaur pinata that each child got a turn to whack. We always let the little kids go first and the last big kid gets to knock it open.  The cake was a volcano and I cooked a regular cake mix in a pan like you would make a doll dress out of so it was mounded on top.  Then I poured a chocolate sauce (melted chocolate chips and butter) over the top and while it was still warm, drizzled orange and yellow frosting (white frosting colored with food coloring and heated in the microwave to pouring consistency) I started at the top and let it run just a little down the sides like lava. Then I placed a few plastic dinosaurs around the base of the cake and made a small sign with a toothpick and cardboard that said happy birthday.  The children each got a dinosaur party bag and got to fill it up with candy from the pinata.