No Soap Radio

I've heard this joke floating around in a variety of forms and have been trying to track down the original source for years.
Have you been told a different variation of it? From whom? When and where?
Please email me so I can add it to the master list of No Soap Radio variations

Here's what I will always remember as the canonical version, since it was the one I heard first:

• A penguin and a polar bear are sitting on an iceburg. The penguin yells, "Radio!" and they both jump in the water.
  Source: Lynette Hays, Spokane, WA, 1975

The complete No Soap Radio catalog (last updated: 12/28/2007)

The original source

Additional Resources

I don't get it