Here’s another fun web site to play with! Thisissand is a simple little program that lets you create pictures with grains of virtual sand that fall from the cursor. You change colors as you like and move the cursor around to plot your picture. When you’re finished, you can submit it to their gallery. There is a gentle sound of sand falling as you "pour" and the whole thing is very calming! My kids made some very elaborate pictures with this today.
(Hint: Click on the tiny gray box in the upper left corner for instructions.)
If you want to follow it with some real life crafts, put some salt in a jar with a few drops of food coloring and have the kids shake it until it’s well blended. Spread it on a foil-lined cookie sheet and bake at 350 for 10 minutes and cool. Do up a few colors and then let them use glue and paint brushes to create a sand art picture of their own. You can also make layered "sand" jars or use this as really inexpensive glitter!