This is not fun with rocks but maybe fun with beans. I saw this coffee maker for camping on the Outside Magazine site. It’s gas-powered and was chosen as one of the best products of ‘09.
But, when I am camping I like simple and fast (is it surprising, that I would like FAST and SIMPLE?) So what I do is make Cowboy (Cowperson?) coffee. There’re tons of ways to make it, but ‘cuz I’m in a hurry, I just boil some water, throw some grounds in the pot (a lot is better than a little) and then let ‘er boil for a bit. Take it off the heat, wait as long as you can, then pour out a big steamin’ cup of Joe while you say “GiddyUp, Give Me A Cup.” That’s all you need to do. (Filter the grounds with your teeth. It won’t hurt you.)