Pat's Backcountry Beverages has come out with a powdered beer concentrate that you place in their carbonating bottle and add water. Instant beer. Perfect for long days out where you don't want to tote around a ton of heavy beer. Beer is, after all, 95% water.
While I haven't tasted Pat's Backcountry Beverages, they claim their powdered beer tastes as good as a premium quality micro brew.