The other night I was making Turkey Burgers for dinner and while making the patties I used my hands to mix the meat and seasoning. The girls wanted nothing more than to help me! Well I didn't want them actually touching the meat, so when I was done I looked up my play-dough recipe and let the girls have at it! I will tell you after the 10 minutes or so prep time it took to make the dough, the girls played independently with their homemade creation for almost an hour-definitely worth the investment! I think they loved being a part of actually making the dough, it made it more interesting for them! 
This book is awesome if you have toddlers. It has a ton of great ideas for home are projects that are experimental and hands on, this is where my play-dough recipe came from.
