Wish i knew this when I was babysitting! Crayon hot rocks: If you have not done this yet, you need to. Simply warm up the rocks in the oven (I did 220 for 10 minutes), then put them on a stack of newspapers (or something else you don't care if it gets crayon in it) and let the little ones go to town. Just remind them it is hot. I have done it with 2 1/2 year olds with no problem. My little lady often brings in rocks for me to "cook" so she can paint them
Another Pinner said: "This kept my 2 year busy for an entire hour and my 4 year old busy for 2 hours! YAY! Drop vinegar tinted with food coloring onto a pan filled with baking soda. Sheer minutes of colorful fizziness!!... Pretty sure we will be doing this soon! GENIUS!