We did Nemo for ds's 3rd b-day party last year. I posted some pics a while back on the Birthday Party thread. We had alot of fun!
I skipped a cake altogether and just did the jello 'aquariums'. Blue jello in clear, 'wavy' plastic cups with a dollop of Cool Whip and then Nemo fruit snacks on top. The kids thought those were awesome.
Games I bought 2 magnetic fishing game sets at the dollar store. We were hoping to be outside but it was raining. So I put a big towel on the kitchen tile floor, filled a large plastic bowl halfway with water. And then the kids took turns fishing. (I bought 2 sets to have more fish to choose from and also in case a fishing rod broke.) There was water splashed on the floor but it was no big deal. As each child finished they got a Nemo tattoo put on their arm.
We also played 'Find Nemo'. Again, I expected to be outside but we adapted. I had one large Nemo sticker that I put in a snack size baggie. Then I put other Nemo characters in more baggies. The total # equaled the # of kids 'searching'. I hid them throughout the living room. Each child was allowed to search until he/she found ONE bag, then they had to stop. (To allow for the little kiddos to have a fair shot.) The one to find 'Nemo' won a special prize. All the kids got to take home their stickers.
We also played a version of musical chairs with a big blow-up clown fish I got at the dollar store. Music on, pass the fish, music off, whoever is holding the fish is 'out'.
That was it for games.
Since we had it at 10am I didn't serve a meal. We had a little buffet table set up with Nemo themed munchies. I made edible fishing rods with pretzel rods, a piece of thin red licorice tied onto one and and then tied the free end of the licorice around a gummy fish. Then placed them all in a cup. My ds and all the kids went crazy for these.
We also had crocodile 'cheetos' (I forget what brand those were), bowls of Nemo fruit snacks and sharks, fishy crackers, pineapple and mandarin oranges. Oh and popcorn. I served blue kool aid (the unsweetened kind, just lightly sweetened by me).
For decoration I bought several colors of blue crepe paper and hung it so it was straight down to the floor with the pieces right next to each other from our fireplace mantle, our sliding glass door and the railing from the 2nd floor above. (Sunken family room.) With the ceiling fan on low blowing the pieces they would wave slightly...giving the effect of water. It was cute.