For my daughter's 6th birthday, she wanted an art party. The guests ranged in age from 4 to 10 and was a mix of boys and girls.  I set up "centers" around the back porch and backyard. When each guest arrived I immediately had them start at the tye-die center.  I bought inexpensive white t-shirts for each child and wrote their name on the tag. Then I let them rubberband their t-shirt, showing them some of the simpler techniques used in tie-dying.  The favorite and easiest was the mystery tie where you ball up the t-shirt anyway you want and put as many rubberbands on it as possible. Then I had small squirt bottles (cleaned out ketchup & mustard bottles, shampoo bottles, or anything similar) I filled with water and added a few squirts of art paints, the kind you get very cheaply at craft stores.  The kids squirt different colors into the shirt and you let it sit while they go do other things.  Towards the middle of the party I had an adult help unroll the shirts and hang them out to dry.  Each shirt is very unique and they are totally washable. The colors aren't as vibrant as real tie-dye, but it works well for kids.  For the other centers, I had a small table with homemade play dough and lots of cookie cutters for the little ones to play at.  Then there was a table with craft sticks and foam shapes with bottles of glue. The kids could make anything they imagined and boy did they! Another station had the instructions for making dragonfly sun catchers with metallic pipe cleaners and beads. The hit of the party was the cake decorating.  I made a small 4" cake for each child and frosted with white icing (you can also use cupcakes). I put out a variety of sprinkles, sugars, gummy bears and candies. I also had the little parasols, which every child had to have. I even found edible paper and food coloring markers at the craft store so they could draw a picture, cut it out and place on the cake if they wanted.  Some of the kids wouldn't eat their cake afterward because they wanted to take it home to show their parents! Since it was all outside, the clean-up was easy and there wasn't need for many decorations. Lastly, we had a pinata.  For goody bags, I had large colored bags for each child to put all their creations in and the candy from the pinata.  I left it open for the kids to play on our playset if they wanted, but every single child kept busy the whole time making their creations.  It seems like this party would take a lot of time to prepare, but it really wasn't any more than other theme - and my daughter absolutely loved it!!!