Peterman's Eye has a neat post analyzing (okay, more like gently 'splaining) the classic "man walks into a bar" joke. Includes some of the best groaners I've read in ages, such as:
Inanimate objects can walk into a bar: Three fonts walk into a bar. The bartender says, "We don't serve your type in here."
And my favorite:
A duck walks into a bar. And he says to the bartender "Got any grapes?" The bartender says "No, I don't have any grapes." The duck walks out, sorely disappointed.
So the next day, he walks back into the bar, asks the same question, gets the same answer.
The day after, he walks back into the bar, and again, asks the bartender, "Do you have any grapes?" The bartender, having still not figured out why this duck seems to think he may have some grapes, says to the duck, "No, and if you come back in here tomorrow and ask me if I have any grapes, I will nail your bill to the bar!"
The duck frowns, turns around, and walks out of the bar. So the next day, the duck walks back into the bar, and asks the bartender "Got any nails?"
The bartender says, "No."
So the duck says, "Got any grapes?"