At young children's parties, I always like to use a centers" approach. This allows kids to "play to their moods" and socialize freely. Even little ones like that! For a Spongebob party I used many of the excellent ideas already on this website for invitations decorations food and games.  However my child really enjoys crafts and so I wanted to add an art activity that they could do easily and could potentially double as a party favor. The solution: Bikini Bottom Zen Gardens. These are little trays that kids can use as a desktop sandbox. Before the party we gathered the materials and prepared individual "kits." During the party we set up a "Create Your Own Bikini Bottom" table. As the guests were leaving they either took their completed garden with them or if they didn't have a chance to do one (too busy swimming etc.!) then we gave them the kits and instructions to go.  In each kit we included the following: a flat take out food container with lid a bagggie of sand to fill the container about one inch deep a sponge character a starfish character a paper umbrella (like the kind found in tropical drinks) some shells and pebbles a scrap of terry cloth a bit of clay and "gardening tools." We also had some small decorative items (sequins etc.) markers and glue on the table. Here's more info about each. Our trays were obtained for free from a local fast food place.  They were about 9" x 5" x 1-1/2" ovals black on the bottom and with a snap on clear lid.  These worked great because they make it easy to store the garden between uses. We used clean play sand (because it is inexpensive) but you could use craft sand if you want to add color or dye the play sand with food coloring. Our sponge characters were made from regular kitchen sponges. We got four from one sponge. Just glue on googly eyes. You can also press in small pipecleaners for arms and legs.  Our starfish characters were made from model magic. We used a tiny star shaped cookie cutter and then molded each leg slightly before letting them air dry.  We added googly eyes to these as well.  The paper umbrellas can be purchased inexpensively in bulk. Tiny colorful shells pebbles and other embellishments can also be purchased in bulk from craft stores or from a number of sources online. Our terry cloth was used as a beach towel for the sponge character so pre-cut to size accordingly.  We used old brightly colored kitchen towels but you could easily cut up an old beach or bath towel or get a fabric remnant. You can also make seaweed. This can be done easily by breaking up some twigs dipping them in glue and then rolling them in green sparkles.  Finally our "tools" were purchased in the party store. We use small brighly colored plastic cocktail forks (as rakes) and also swizzle sticks. All you need then is some instructions for your guests and maybe a sample.  To make a Zen garden do the following: Write the child's name on the underside of the tray. (We used a mettalic sharpie to write on the black plastic.) Stick a small ball of clay inside to the tray's bottom.  Open and insert the umbrella into the clay.  Pour in the sand to fill the tray almost to the top of the base. These are the only "permanent" fixtures.  Everything else is placed and moved by the child over and over. That's the fun!  To start the child should:  Lay the terry cloth down on the sand to serve as a beach towel. Place the sponge and starfish characters.  Add in some decorative shells and pebbles and other "treasure." Use the fork and stick to make designs in the sand. Kids can personalize their gardens with stickers and their characters with the markers (add hair? a tie? pants?). Just fold up the umbrella and snap on the lid for transport.  We refrained from trying to re-create Spongebob and Patrick themselves opting instead to let the kids name their own characters.  This freed them up from trying to be copycat artists. Our gardens were also very colorful (sponges shells stars tools all were brights) but you could opt for pastels or naturally materials if you like. We pre-glued the eyes and pre-assembled the kits because we had some very young children and alot of kids at the party but if you have fewer kids or older kids you can give them more choice and more responsibility.  The greatest thing is that this activity satisfied my child's desire for a party craft and my desire to have a reasonably priced favor that fit the theme and that kids would love to do and take home. Parents love it too because the kids can play with their gardens over and over!  You can also add to your garden especially with items made for dollhouses or christmas ornaments or scrapbooks or jewelry. I found a little Tiki Monument and am looking for a pineapple for my child's garden. Because everything is moveable when they outgrow Spongebob they can just substitute different characters or objects. "