Jay Leno - who turns 66 today - is best known for riffing on former President Bill Clinton, who was the butt of 4,607 of the 44,000 jokes told during Leno's 22 years of hosting "The Tonight Show." But marijuana also featured prominently in Leno's comic repertoire. Here's a sampling of Jay's best marijuana moments.

1. Leno prefers sweets to sativas

Jay was put on the hot seat in 2012 when Halle Berry asked him if he ever smoked marijuana. "I'm not a pot smoker," Leno pleaded while Berry scoffed. "I was always the designated driver," he explained, claiming that his friends always said, "'Leno, you drive. We'll get high.'" But he did admit to enjoying the munchies without the high. "I like cupcakes," he told Berry.

2. Marijuana without the high

In 2012, researchers in Israel announced that they were developing a strain of marijuana that eliminated the high because it had virtually no THC. Leno demonstrated the difference between high and not high by comparing the version of "One Toke Over The Line" performed on The Lawrence Welk Show with the version performed By Brewer and Shipley.

The one performed "with the high":

And the one "without the high":

Yes, Lawrence Welk did describe "One Toke Over the Line" as a "modern spiritual" song at the end.

3. Anti-pot propaganda

When California prepared to vote on legalizing recreational marijuana use in 2010, Leno imagined that the biggest opponent would be the beer industry. So he put up a mock anti-legalization ad on behalf of the brewers.

4. Kevin Smith's cure for nicotine addiction

Leno began his September 2011 interview with Kevin Smith with a check-up on the director's health. When Smith was last on "The Tonight Show," he promised Leno he would quit smoking cigarettes. And he did...by smoking something else instead. "I've been off cigarettes for three years. And it was very easy. I just simply started smoking weed instead." Smith added that smoking marijuana made him more productive and ambitious, but Leno and Heidi Klum weren't buying it.

5. Debating pot policy

Leno made a lot of marijuana jokes in his tenure behind "The Tonight Show" desk, but he also had a few serious conservations. In 2010, former Congressman Barney Frank debated cannabis legalization with Leno, who didn't see the point in changing America's drug laws. "Smoking marijuana is essentially legal now," Leno said. "You can get it anywhere, and if you get caught, it's the most minimum--"

"But why have hypocrisy?" Frank said. "Let's make it legal....I think as a general rule, the government shouldn't be trying to live people's lives for them."

Check out the full debate, where they talk about legalizing and taxing other vices, keeping cannabis away from kids and the effect legalization could have on the American economy. The debate about marijuana starts at the 2:45 mark:

h/t The Washington Post