Though I totally didn't have time to dye eggs this year, I want to remember about this idea for next year. Go here for the link or read some of the coloring ideas below (in case the link goes dead later - I seem to have that problem for fun ideas like this).
Bluish-Gray: Mix 1 cup frozen blueberries with 1 cup water. Bring to room temperature. Remove blueberries.
Dark Pink: Cut 1 medium beet into chunks. Add beet to 4 cups boiling water. Stir in 2 tablespoons vinegar. Let cool to room temperature. Remove beets.
Yellow: Remove the peel from 1 orange. Add peel to 4 cups boiling water. Stir in 2 tablespoons vinegar. Let cool to room temperature. Remove orange peel.
Lavender: 1 cup grape juice and 1 tablespoon vinegar