We started out by buying some rainbow and green napkins, table clothes and Happy Birthday sign from The Party Store. Searched Pinterest for DIY ideas and did not come up with much, I guess it was all up to me. I found some free coloring pages and enlarged them on my scanner/printer. We, including my daughter, colored these pages and cut them out to use on the wall. We also used my daughters' Muppet stuffed animals to hold the balloons.
For the cake I found a great tutorial for creating kids characters on cakes at Brass Tacks and Basics . I used this tutorial to create Kermit and Piggy on the cake. I tried to create the lettering with this technique but it did not work, I am not good at righting with icing. My daughter had a great time at her birthday party.