We haven't made any eggs since the clog from hell incident over the weekend, so no egg shells yet. We only use Dunkin Donuts coffee, so our coffee isn't bitter anyway. I did find this, it has some recipes. http://www.coffeefaq.com/site/node/51
Brent, i don't drink coffee (consistently nayway) so I've started saving all my eggshells to mail to you.
I hope you don't mind I don't bother washing them though, that's alot of extra work.