A pretty good joke told to me by a coworker

One day little Billy approached Mr. Johnson's house and knocked on the door. After they exchanged a few pleasantries, little Billy asked Mr. Johnson, "Sir, I noticed ya got some milkweed growing in your backyard, mind if go back there and get some milk?" Amused by the request, Mr. Johnson replied, "Son, knock yourself out." knowing full well that he couldn't possibly get milk from milkweed. Sure enough, Billy came back to Mr. Johnson with 2 pails of milk. Little Billy thanked the now shocked and speechless Mr. Johnson and went on his way.

The next day Billy knocked on Mr. Johnson's door again. "Afternoon Mr. Johnson, I noticed ya had some buttercups growing in your backyard, mind if I get some butter?" Curious this time around, Mr. Johnson replied, "Sure son, go right ahead." knowing full well he couldn't possibly get butter from a buttercup. Sure enough, Billy came back with 2 buckets of butter. Again, Billy thanked a now even more shocked and speechless Mr. Johnson and went on his way.

The next day little Billy knocked on Mr. Johnson's door for a third time. Mr. Johnson, very intrigued by little Billy's strange requests eagerly greeted the young man. "How can I help you today son?" said Mr. Johnson. "Well sir, I noticed ya had some pussy willows growing in your backyar-" and before Billy could finish Mr. Johnson interrupted, "Hold on Billy! Let me go get my boots!"