After posting the Yip-Yips, I did more reading about Sesame Street and Jim Henson, and stumbled upon these classic 1960s Wilkins Coffee ads, which starred Jim Henson's muppets. 

...The greatly increased exposure led to hundreds of commercial appearances (mostly for Wilkins Coffee) by Henson characters through the 1960s.

Being puppets, they have been able to get away with a greater level of slapstick violence than might be acceptable with human actors. A good example is one of the early coffee ads. A Muppet is poised behind a cannon seen in profile. Another Muppet is in front of the barrel end of the cannon. The first Muppet says, "How do you feel about Wilkins Coffee?" The second Muppet responds gruffly, "Never heard of it!" The first Muppet fires the cannon and blows the second Muppet away... then turns the cannon directly toward the viewer, and ends the ad with, "Now, how do you feel about Wilkins Coffee?"

Here are several videos containing the classic ads:
Wilkins Coffee 1, Wilkins Coffee 2, Wilkins Coffee 3, Wilkins Coffee 4, Wilkins Coffee 5

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