I cannot believe how easy this is and how much I've seen these sold for at craft shows!
Make a Silicone Mold from Silicone Sealant - super easy and a LOT cheaper than buying mold making supplies
This homemade clay recipe only takes two ingredients and 10 minutes! Oh, and it is so much cheaper than the store bought model magic!!
Make your own polymer clay - Tutorial porcellana fredda (pasta polimerica fai da te)
Here's a tutorial on how to draw hands. There's an entire list of drawing tutorials.
Erupting baking soda paint - combining art and science with one simple paint recipe!
Turn Dried Out Markers into DIY Alcohol Ink That Works on Glass, Metal, and Plastic « MacGyverisms