A Toy Story 3 themed ad for US Postal Services flat rate boxes had Hamm the piggy bank informing the group about the service while wearing a postal hat and bag. Hamm is voiced in the films by John Ratzenberger, who's most known for playing a postman on this one TV series...
Ratzenberger also was the spokesman for Pitney-Bowes Personal Post Office.
With credit to The Other Wiki for pointing out the reference: The original ad campaign for XM Satellite Radio featured famous musicians falling from the sky and crashing into various mundane settings. David Bowie fell into a motel room, looked skyward and murmured, "I'll never get used to that."
There exists a 5% cash back discover card commercial that mentions Ned the Head. The narrator of the commercial just happens to be the actor who played him.