Here is another recipe that I found and would like to try making it with my daughter :)
Pour 1/4 cup alcohol into a baggie.
Add 10 drops (more or less depending on shade you want) of food
coloring to the alcohol.
Add 1/2 cup pasta to the alcohol.
Seal the baggie and allow the pasta to absorb the color for about 5 - 10
minutes. Turn the bag every couple minutes to evenly coat the pasta.
With a slotted spoon, scoop the pasta out of the baggie and allow to dry
on a brown paper bag for about 1 hour.
Rigatoni makes good beads for necklaces.