At the border, a man rides up on a bicycle with a sack on the luggage rack.
The customs officer stops him and asks, “Do you have anything to declare?”
“Nothing,” the man replies.
“And what’s in the sack?”
“Sand.”
The officer inspects the sack. Sure enough, nothing but sand.
The next day, the man returns on the bicycle with another sack of sand.
Again, the officer checks it. Nothing but sand.
This goes on every day for a week.
By the eighth day, the officer has become increasingly suspicious. He sifts the sand. Nothing.
The man continues crossing the border every day. After two more weeks, the officer finally sends the sand off to a laboratory for analysis.
The results come back: nothing but sand.
Another month passes. By now, the customs officer is losing his mind.
Finally, he pulls the man aside and says, “Listen… off the record, between you and me, I promise I won’t tell a soul. But you have to tell me what you’re smuggling.”
The man looks around carefully, leans in, and whispers:
“Bicycles.”