I've noticed that at Starbucks they sometimes have a bucket by the door filled with bags of used coffee grinds for people to take and use as fertilizer for their gardens or compost piles. Of course, my first thought was hair coloring.  ::) But would just the grinds be as effective? Not being a coffee drinker, I don't know what the difference is. I usually use a scoop of my mom's instant stuff for my hair, which works pretty well.
The label on the bags say that most of the acidity has been removed from the grinding and that the grinds are high in nitrogen. Would this make any difference in how it affects my hair?

I would think that the used grounds would be less damaging to your hair than fresh brewed coffee.   I'm not a coffee drinker myself, but I know that coffee is acidic.  Used grounds would probably be less acidic.

It would certainly be worth a try!

Thanks bikerbraid! I'll try it with my next washing and see how it goes.

And hey, if all else fails, at least it'd be a nice treat for the compost pile.  :)