Wonderfully deluded slashdot piece on using coffee grounds as a biofuel.
This is a great example of the misapprehension many people have about fossil fuels.
There are two vital facts about fossil fuels:
1. They burn
2. They are very, very, very cheap.
It's the cheapness that makes them hard to replace - there are plenty of other things we could use, but none that are as easy to obtain as drilling a hole and pumping stuff out. One commenter pointed out that the year's supply of coffee grounds would replace less than 3 hours of the USA's gasoline consumption, but the real point is that the insignificance of a few pounds of stuff that still has to be refined or processed in some way should have been completely obvious to everyone.