Our daughter just turned 3, and we decided on an "Under the Sea" theme for her. Invitations: I used blue watercolor vellum on top of cream colored card stock, attached together by blue silk ribbon at the top. It said "You are O-Fish-ally invited: To come under the Sea, Isabelle is turning three! The invites were then cut out using scalloped scissors to create a wave effect, and decorated with sea life stickers. Food: All the food was labeled to match the theme. For the children, I make octopus from hot dogs, cut 8 tentacles in the bottom half, and then heated in water-it makes the legs curl. We had a veggie platter labeled "sea plants", blue punch labeled "ocean water"-it had an ice ring with gummy sea life frozen in it. Meatballs labeled "turtle eggs", a snack mix (pretzels, nuts, raisins, fish crackers) labeled "penguin food". It was served in a clean beach pail, and had a stuffed penguin eating from the pail. Little spiral tortilla wraps labeled "snail shells" served on a large fish platter. Rather than icecream, I made a pudding dessert labeled "Beach pail sundae"-it was vanilla pudding, whip cream, crushed oreos, served in a beach pail.The top of the dessert was covered in crushed cookie crumbs, and homemade chocolate sea shells. Cake: the cake was a 9x13 cake iced in blue icing. It was made to look like an ocean scene.  At the bottom-crushed graham crackers for sand, chocolate rocks (they look real!) sea weed made from green fruit roll, a sea plant made from blue sour stick candy, colored white chocolate sea shells (green, yellow, orange, purple) and little plastic fish swimming around. I also made a 3-tiered cupcake tray. Each cupcake was decorated with blue icing, a pick (Babykakes.com)of either octopus, turtle, oyster or star fish, then some chocolate rocks, and a colored chocolate sea shell. The cake table had streaky water blue gossamer fabric woven around the cake/cupcakes, and a platter of the homemade chocolate sea shells. Decorations: the childrens plates/napkins/cups were in the sea life pattern from birthday express. I also had the sea life "blowouts" decorated with a sea turtle at each childs plate. All tables were covered with blue table cloths, and multi-colored sea life confetti. I had tissue tropical fish hanging from blue curling ribbon throughout the house. The bar area was covered in blue plastic,and then hanging from the bar were streamers of green crepe paper so it looked like sea weed, with bright construction paper fish attached to the sea weed. I had a large mylar fish balloon free floating, as well as a dolphin mylar, and several dozen blue, aqua, clear and white balloons all from blue ribbon just free floating up against the vaulted ceiling. It gave the impression that you were under the water. I also had gotten a refrigerator box and had painted it with tempra paint to look like an ocean scene, with a giant shark on the front. Cut out the sharks mouth, and cut a door, and the kids could go into the box and look out the mouth..it looked like they were inside the sharks mouth. This was most of the kids favorite thing, and it is still up in our living room because Isabelle loves it. It made for really good pictures. Games: We burned a CD of all sea themed songs (a lot from Little Mermaid and Nemo) and used the music to play "Pass the Octopus" where kids sat in a circle and passed a bean bag octopus. Whoever had it when the music stopped got a prize. With 3 year olds-we made sure everyone got a prize. We played "Stomp the starfish" with a star shaped pinata. Kicking it, rather than swinging at it to break it open-safer that way. We also had a pull string pinata in a sea life theme. I filled the bathtub with water, and the kids fished for foam floating fishes.  Treat bags were:fish squirts, fish suckers,fish pencils, fish bubbles (all from Oriental Trading),and shark fruit "bites" and the candy from the pinata. All the kids had a great time, and I hope I created a good memory for my daughter.