Henna

Well, I'm still in search of a natural hair solution.  I've tried the baking soda and vinegar.  After awhile my hair gets brittle, and even the organic/natural shampoos only work for a while and then my oily scalp comes back.

Soak a Pu'er teabag in 9 oz of boiling water and seep for 30 mins 
Update: I added the 1tsp coffee granules to the Pu'er

Take 100 g of henna powder and add the Pu'er to it (sans tea bag!)

Mix in juice of half a lemon

Add 1 tsp of coffee granules (not the ones from the 3-in-1 mixes!) and 1 egg.

Update: Oops! Sorry, actually, I added the 1 tsp coffee granules to the Pu'er tea.

After mixing you shld get this gooey and smelly mud-like mixture.  Then let it sit for at least 3 hours for the ingredients to react with one another.  I just put mine in the fridge.  I have shoulder length hair and it gave me up to 3 applications.

Then when it's done, here's what you do with your hair:

a) wash your hair to get rid of any residue

b) let your hair dry for a while so that it's slightly damp and not dripping with water

c) remember to wear an old T-shirt or have an old towel draped over your shoulders. Oh, and wear gloves as well. 

d) massage in lots of the henna mixture into your hair (don't go over your hair line!) and then put everything under a hair cap.  Add another towel if you want to try and "steam" it.

e) Leave in hair for 3 hours (at least!)

f) Wash out thoroughly!!

OK, my hair's black, so the result I got was shiney and easily manageable black hair with hints of dark brown in the sunlight.  I'm not really sure what would happen to other hair colours but it would be good to test it out on a few strands first!   Although the smell was unbearable during the application, my hair ended up smelling okay after washing out everything. :-)