There’s one in which he “washes” invisible dishes in the sink while she talks, and it’s not for comedic effect.
He and his (8th) wife recently separated after more than 35 years together due to him accusing her son (by a previous husband) of elder abuse (testifying about it before Congress in fact) and embezzlement.
I think the Anita Bryant endorsement and theme song singing for the Florida Citrus Commission is right up there. In the 70’s, this former beauty queen sang “a day with out orange juice is a day without sunshine” and was America’s most wholesome symbol of wholesomeness.
Then she got angry at a an anti-housing discrimination ordinance in Miami and founded “Save the Children” (or some such) crusade against the gays. She decreed that all gays were hunters and recruiters of innocent children. She went on the become an outspoken hater of things she defined as “un-Christian”. The orange juice folks couldn’t dump her ads fast enough and she sort of disappeared off the radar.
Looking at one of the old Chesterfield ads with John Wayne endorsing the smokes with the knowledge that the Duke would battle cancer until it defeated him always saddens me.
Practically every he-man of the era plugged some brand of cigarettes to convince would-be smokers that not only was it cool, it was indicative of the attitude, “any fool can quit smoking but it takes a real man to stand up to lung cancer.”
The he-men who died of lung and repiratory diseases might have wished they’d been a little more selective in how they added to their incomes.
The thing that’s really puzzling nowadays is what product or activity will, in years to come, be seen as just as ridiculous for spokespeople to be investing their credibility in. This thread has identified some of them, but we must be missing The Big Ones.
Shatner also was the spokesman for promoting bathroom “regularity” by eating All-Bran. Though these ads, as I remember, had a certain self-referential sense of humour about the whole thing.
In fact, Shatner’s been in so many commercials, his commercials have their own fan page! 
Original Takes for Orson Welles Wine Commercial - YouTube Orson Welles FTW (or loss)
and The Critic’s send-up… Orson Welles in The Critic - YouTube
Erik Estrada pitching California real estate before the bubble.
Refrigerator Perry was once the spokesperson for Big Ass Fans.
I’m surprised no one has mentioned what was arguably the most ill-advised celebrity endorsement ever, namely former first lady Eleanor Roosevelt’s television commercial for Good Luck Margarine. Despite the criticism, she apparently had no qualms, since she earmarked the $35,000 fee she collected for her favorite charity. The small ding to her dignity was worth the benefit she reasoned.
See the ad here:
He’s good, almost kept a straight face.
he was funny at it and he’s no stranger to making money by any means neccessary.
It wasn’t lung cancer that got him:
Holy fuck.
She also spoke out very judgmentally against divorce, and then got divorced herself.
Radio/TV show host Arthur Godfrey used to do various types of insurance and medical commercials in the afternoon when I was a kid.
I didn’t know who he was at the time because he was a bit before my day, but I’ve since learned that those commercials were kind of sad in their origin. Godfrey was a real life Norma Desmond type character- he went from a superstar to a total has been almost overnight after he quit his show. He thought he would take a couple of years off and then pick up his career where he left it, but he found out nobody was really interested; his ratings had been respectable but in decline when he quit, and he was so obnoxious and authoritarian that nobody wanted to work with him, several shows already had the super important 18-40 something population sewn up and he wasn’t really missed that much by his former fans. His most diehard support was among older listeners and viewers who were not the ones the networks were after. Consequently he could not get work.
He was not desperate financially. He was very rich in fact, but like Norma he was desperate for an audience. He did those commercials not because he needed the money, but because it was the only work he could get.
I’ve always heard celebrities are offered tractor trailer loads of money in Japan to do commercials and ads for embarrassing or mundane things. They fight tooth and nail to keep those commercials and ads from showing up in the U.S. I’d love to see some of them.
11 most ridiculous Japanese ads with American celebs:
http://marquee.blogs.cnn.com/2011/07/29/11-most-ridiculous-japanese-ads-with-american-celebs/
Also a key point in Lost in Translation.