For my son's 5th birthday, he wanted to "go fishing".  Since his birthday is in October, we came up with the next best thing.  The invitations had a fishing rod glued to the front (made out of a twig and string. The string was tucked inside the card with a paper clip bent into a hook shape and a paper fish attached to it with the party info on it. The front had a wooden sign drawn on it with the words "Fishing Hole" on it. The kids were instructed to wear "old fishing clothes". Since the weather wasn't too chilly, as the kids arrived we played "shark tag" in the back yard.  Then we had a bait hunt (gummy worms in little plastic bags).  We then moved the party indoors. We had hung green streamers straight down from the ceiling for seaweed with blue balloons hanging down for bubbles and cutout paper fish hanging as well. We put blue plastic tarp under the table to catch any messes and look like water. We replaced the light bulbs with blue ones for a cool blue ocean effect. The tablecloth was brown craft paper and we put a tackle box on the table filled with crayons and stickers for them to decorate it.  There were fish bowls filled with goldfish crackers on the table.  I had baked fish shaped cookies for everyone and I had a recipe for cookie paint.  Each child got to paint their own cookie to take home. For the next game, we did two children at a time, put a garbage bag smock on each and in front of each of them was a pie plate filled with chocolate pudding and gummy worms. They had to put their hands behind their backs and "bob for bait". The cake was a blue ocean with gummy fish and icing starfish on it. Before they left we had a large box decorated with an adult behind it with the goodie bags (gummy worms and fish, a real starfish, etc.) and they fished for their bag. It was a blast!