Candyexperiments.com shows how to test the acidity of any fruit flavored or sour candy using just warm water and baking soda. They even have videos for lemon heads, nerds, piie sticks and war heads.
Starwars.com has a tutorial on how to make a Death Star pinata. It looks a lot more difficult to make than it actually is. The trick is to use masking tape to control for the solid lines.
No time for flash cards shows how to make a leaf bouquet by rubbing crayons onto leafs covered with regular copy paper, which in turn transfers their seams onto the paper. They even have an idea for a vase - a paper towel roll.