Stan Kegel posted this to the groaners listserv.

All afternoon a real estate agent had been showing a young couple empty houses. The ones they loathed always seemed to be available, but others had invariably snapped up the ones that struck their fancy. Finally, they came to a house at the very edge of town and fell in love with it.

“Please,” they begged, “tell us that this one we can have.”

“It’s yours,” beamed the agent. “It’s last, but not leased!”