Gracie and I played with Oobleck today. It was our first experience with the goop, and she LOVED it! I honestly think out of all the Toddler Activities we've tried, this is her favorite so far. She played with it for over an hour! Even then, I had a little trouble getting her to the tub to clean up. If you plan on trying this-which I highly recommend-don't put food coloring in it. One of the web sites I found about it said it's more fun with color so I put blue coloring in it and now Gracie and I could pass for having a bit of Smurf DNA in us.