We had a paleontologist party for my son's 4th birthday party this year. The children had so much fun trying to find dinosaurs and they learned about what scientists do too!  The invitations were an outfit of a 1930's African explorer/scientist that we put dotted lines around to make it look like a paper doll. We printed it on cream colored card stock. We used a bones font on the computer to say please join us for a dinosaur excavation.  The best part of our decorations was the stone patio we were building and hadn't finished.  We put yellow and black "hazard" tape around it and put up signs saying it was a "t-rex excavation"! As the kids came in we gave each of them a pithe (straw) hat, binoculors (from Oriental Trading) and a dinosaur tatoo.  When everyone was there we gave them each a brown bag with handles and either a shovel or sand sifter toy.  We buried dinsaurs of all sized (Dollar Store and OT) in the sandbox and wheelbarrow (we bought the sand from Home Depot).  We told them that scientists dig for dinosaur bones and to go at it.  I thought this would take 5 minutes and be a quick event, but the kids loved it and dug until they found every last dinosaur.  Then we came into the house and I had a storyteller/musician read a few stories and sing some songs about dinosaurs. While they were inside, I was outside burying dinosaurs eggs (OT). After they were done, I said that a dinosaur had been and laid all kinds of eggs. They had a great time finding the eggs.  Afterwards, we had a sheet cake with a T-Rex on it. We opened gifts and took a photo of each child with mine before he opened their gift.  I included a copy of the photo with each thank you note.  The thank you had a t-rex on it saying "excavation completed!" thanks for your help.  Each child took home a hat, binoculars, all the dinosaur and dinosaur eggs they found and a package of dinosaur gummies I put in a clear cellophane bag and tied with a ribbon.  We had so much fun being creative with this theme and the kids really enjoyed it too!