If you haven't colored rice before, here's what you need:
1 TBS vinegar
1 cup rice
Put the vinegar and food coloring in the Ziploc. Add as much food coloring as you like. I usually put about 5 drops. Add the rice to the bag and squish around until it is evenly coated. This is a great chance to get little ones involved as long as they don't try to run off with the bag and rip it open. ;) This technique is supposed to work on dry pasta as well. That's next on the to-do list for me.
Lay the wax paper on a cookie sheet and spread the rice out on it. I dry mine outside because the smell can be a bit overwhelming and it's warm and sunny in Texas this time of year. The vinegar smell does go away, I promise. It dries amazingly quickly, and then you're ready to go!
The bottle pictured above has blue and green rice in it. I was using "neon" food coloring, so the green looks a bit more yellow than I had anticipated. Experiment. Rice is cheap, so have fun! Oh, and don't forget to glue the lid on the bottle. You do NOT want colored rice spilled all over your house. :)