Collecting it out of a fountain...
A farmer was going to town with a fox, a goose and a sack of corn. When he came to a stream, he had to cross in a tiny boat, and could only take across one thing at a time. However, if he left the fox alone with the goose, the fox would eat the goose, and if he left the goose alone with the corn, the goose would eat the corn. How does he get them all safely over the stream?