The standard reply is to use it in your lawnmower or old truck. something that won't be fuel picky.
Speaking from experience here (and in this case the friend, really is a friend), if you dump the gas into a vehicle, don't fill the darn thing up. Put in a little, then dilute with fresh gas. If you dump the whole thing in, you just might have a truck that won't run.
The other thing is to ask around at a marina. Usually you can find someone who will take it off your hands, but my experience has been that while they won't charge you, they won't pay you either.
When I took about 70 gallons off one time, I put about 35 gallons into 5 gallon jerry cans which I used slowly in everything and let the marina yard guys have the rest. If I had to do it again, I'd just let them have it all. It was a real pain in the you know what hauling and siphoning all that gas.
