April 20, popularly known as 420, is a day for die-hard marijuana smokers to gather in solidarity and do what they do best.

Pot plays a supporting role in some cult comedy favorites, commonly referred to as stoner movies  -- a genre established by Cheech and Chong and their mile-long spliffs in the 1970s.

Here are some of the most popular stoner movies that stoners and abstainers alike can enjoy on this 420 Friday:

Dude, Where's My Car? (2000)

Before Ashton Kutcher married Demi Moore, and when Seann William Scott was on the heels of his turn as Steve Stifler in American Pie, the two goofballs made this bro-mantic stoner movie together. At one point, a character even gets a dog high-- which we don't suggest you try at home.

Road Trip (2000)

Weed plays a role in this movie about a college student who accidentally sends a sex tape to his long-distance girlfriend -- starring him and another woman. The slapstick race to beat the mailman involves marijuana. A whole lot of it. Oh, and Tom Green plays with a mouse. Classic.

How High (2001)

This film, which rappers Method Man and Redman in the leading roles, is about two stoners who get high and then ace their college entrance exams. They do so well they end up at Harvard.

Harold & Kumar Go To White Castle (2004)

John Cho and Kal Penn star in the comedy, the first in a series, about two stoner slackers who get high and try find a White Castle to satisfy their subsequent food cravings. The other films in the series are Harold & Kumar Escape from Guantanamo Bay and A Very Harold & Kumar 3D Christmas. That last one is definitely not for children.

Super High Me (2007)

Comedian Doug Benson, whose schtick often involves marijuana, decided to avoid smoking the drug for 30 days for this documentary, and then smoked it for 30 days straight. Inspired by the Morgan Spurlock's documentary Super Size Me, the film includes interviews with fellow marijuana supporters who want to see the drug legalized.

Pineapple Express (2008)

The usually put-together James Franco plays a quintessential slacker stoner in this hazy action-adventure story. Seth Rogen -- who enjoys a spliff every now and again on and off scren -- plays his sidekick.

Your Highness (2011)

The point of this stoner movie, which takes place in a magical medieval time, was never quite clear -- maybe that was the point? -- but it does feature Black Swan actress Natalie Portman in a feisty warrior woman kind of role.