Comedian Jimmy Fallon has a knack for two things: celebrity impersonations and getting guests on The Tonight Show to open up about cannabis, whether they're discussing activism, dishing embarrassing marijuana anecdotes or collaborating on cannabis sketches. In honor of the host's 42nd birthday, here are his best marijuana moments.

1. Seth Rogen's 'Schwag Hut'

Outspoken cannabis connoisseur Seth Rogen did not disappoint fans of his cannabis comedies when he stopped by The Tonight show in 2013. The Canadian comedian agreed to do a "fake arms sketch," which features Fallon and guests using mannequin arms instead of their own hands in a scene. Rogen's took place in 'The Vancouver Schwag Club,' a fictional dispensary stocked with jars of strains with names like Yankee Doodle Dankee and King Kong Kush, which Rogen's arms smashed on the floor.

The best part was when Rogen tried to roll a joint with the mannequin arms and then accidentally set one on fire.

2. Seth MacFarlane's Cannabis Thanksgiving

When Family Guy creator brought his dad along to the show in 2015, the conversation quickly turned to MacFarlane's liberal upbringing. "I remember one point, my parents saying to me, 'It's normal for you to want to try drugs. And all we ask is that you do it here in this house with us," the comedian said despite his dad shushing him. "I think the idea was that it would remove the temptation."

And the experimental approach to cannabis parenting worked. "It did. It did. I didn't smoke pot until I was 28. So hats off. Well done."

But when he did start smoking, he took his parents up on their offer by having a smoke session with his dad -- a former folk singer - at Thanksgiving.

3. Snoop and Willie Get the Munchies

It almost sounds like a corny joke: Snoop Dogg and Willie Nelson meet up in Amsterdam and head to KFC to cure a case of the munchies. But The Doggfather told Fallon the story is true when he stopped by the show in 2015. After playing dominoes and 'enjoying life' in Nelson's hotel room, the two cannabis icons went out for a bite. Things got a bit awkward when they reached into the greasy bucket and grabbed the same piece of chicken.

But Snoop handled the situation with class.

4. Nick Jonas' Edibles Erection

Earlier this year, former Disney star Nick Jonas shattered his squeaky-clean image by telling Fallon about his disastrous experiment with marijuana edibles.

"I've never told this story - for good reason," he said before recalling a night of celebrating the release of his last single. "One of my friends' wife said, 'Hey, I've got this weed lollipop. Might want to give it a try.' And I was like, sure - why not?"

He went to sleep that night feeling fine, but he says that everything was in slow motion when he woke up the next morning. Which was a huge problem because he had to host the Young Hollywood Awards that night. 

5. Ziggy Marley's Real Name

Did you know Ziggy Marley's real name is David? The reggae singer opened up about up about the origins of his nickname during a 2011 appearance on Late Night with Jimmy Fallon. "Ziggy is a small joint," Marley confessed as the crowd roared with applause. 

The audience also got a laugh out of Ziggy dodging Fallon's point blank question about using cannabis recreationally, which remains illegal in Jamaica despite the Caribbean island's reputation as a marijuana mecca.