The son moves out of the house. The empty-nester parents go through three or four different uses for his former bedroom - goofy scenarios (and a few messy ones) - until finally putting it back the way it was - just in case he decides to visit.
The humor is gentle, silly, touching. A ham-fisted creative might have come up with derogatory, insulting personas and scenarios - like the preposterous notion of Baby Boomers wanting to become narcissistic teenagers again. These folks are loving, a bit lost (who wouldn't be) — and the fun-poking has to do with human nature, not generation-specific stereotypes.
And the spot is well-researched.
The Richards Group is the agency of record, but I don't know if they produced the spot. Stainmaster Carpet has a few of their commercials on the web - but not this one. I hope they put it up (if only so I can download it and use it in presentations).
Addendum, December 19th 2005: They put the spot on the web. Watch it.