Wish You Were Here — Tom Holt

Visitors flock to an Iowa lake where a ghost allegedly will offer up your heart's desire in this contemporary comic fantasy.

It was a busy day on Lake Chicopee, where an eclectic bunch of sightseers and tourists had the strange local residents rubbing their hands with delight. Among them was a young man from England, who was there because he knew about the legend of the ghost of Okeewana and what she promised. Just immerse yourself in the waters of the lake and receive your heart's desire.

The only drawback was that it was Okeewana who decided just what that was . . .

Perfect for fans of Douglas Adams or Terry Pratchett