It happened to some friends of mine with an old pick up. They took it to the gas station to fill it up and the filler neck overflowed. Drove it about 15 miles and it stopped and wouldn't run. They pushed it with a car all the way home and discovered the gas gauge was on empty, as was the tank.
Apparently when they filled it up the tank "burped" and they assumed it was full and drove off. When it stopped no one thought to look at the gas guage, since they "knew" it was full!