Since the last one was so well, received, I'll tell another - although I must give credit to Renaissance Faire performer Axl the Sot, from whose song this joke was plagiarized.
A Scottish guy is visiting Ireland. After a hard night of drinking at the local pub, he decides to go back to his room. He doesn't make it all the way home, and passes out under a tree.
A couple of Irish lasses happen by, and decide to see if it's true what Scotsmen wear under their kilts. After much blushing and giggling, one of the girls says,
"Let's leave him a little remembrance that we were here."
Her friend agrees, and removes one of the blue bows in her hair, and ties it around his manhood.
The man awakens in the morning, needing desperately to relieve himself after the nights' drinking. Upon hiking up his kilt to relieve himself and seeing the "gift" left by the girls, he exclaims...
"Well, I don't know where you've been, me lad, but I see you've won first prize!"
I must pass out under a tree sometime