Crafts By Amanda has 7 cool ways to decorate eggs. Marbled Eggs, Speckled Eggs, Drip Eggs, Rubber Band Eggs, Colorful Chinese Tea Eggs, Stenciled Eggs, & Tie Dye Eggs. Here's a couple photos of her creations:
Gorgeous! I also found a great How To on Disney Family Fun on making leaf print eggs.
It's so easy to do! I wonder how well it'd work with feathers.