I came across this the other day and figured I'd make you guys aware about it.
http://www.compositeeffects.com/fx_silslime.htm

You can also make it by using red glycerine soap, white ivory bars, grate them in a big bowl, squish it up a bit, then add enough water to make it soupy, then add food coloring.

Wait a bit and add a little bit more water. It'll be less and less gooey with how much water you add.

Just melting glycerin bars just smells.

Info supplied by my friend Alison.

I bought a packet of something called Gobbledy-Goop on a recent trip to Hobby Lobby. It's unique in that its recipe doesn't require Borax–just get yourself a cup of warm/hot water and mix to the desired consistency. You also get three color tablets–basically Easter Egg tablets–that you can create various colors with. I wonder what would happen if I used actual Easter Egg tablets?