We had heard about these cola fountains circling 'round the internet and I think my husband saw something about them on The Today Show. Then, the kids saw it done on MythBusters and we just had to try it for ourselves. You need a 2 liter plastic bottle of diet cola (doesn't need to be a name brand, but must be "diet") and a package of mint flavored Mentos. The idea is to get as many Mentos into the opened container of cola as quickly as possible. We made a little paper funnel to help us out. Our biggest fountain used about 10 Mentos. So, open the bottle, set up the funnel, drop in the Mentos and jump out of the way! We had a blast!