A pickle walks into a bar...

A pickle walks into a bar and the bartender says: "Hey, pickel! What are you doing here?" The pickle replies: "Well for starters, I'm celebrating the fact that I can walk."

This is another "walks into a bar" joke. In this joke, the humor lies in the fact that the listener assumes that a walking pickle is normal in the world of the joke, and is then disabused of that notion by the punchline.