Underrated Comedies
 

I'll start.

Planes, Trains, and Automobiles - not overlooked by fans, but by critics it's frequently shut out in the dark (Ebert notwithstanding) as the best effort of Hughes, Martin, and Candy. My favorite comedy ever, one of the rare breed which is at once balls-out hilarious and moving without being manipulative. Similarly...

L.A. Story - "I said I never wanted to see your face again!" A perfect comedy, only saw it for the first time recently. An imaginative blend of wacky satire and love letter to L.A.'s cultural bliss, with a fantastic Steve Martin (once again) and a surprisingly attractive Sarah Jessica Parker.

Night Shift - am I the only one who'd consider Michael Keaton's performance in this something of a gift from God? The epitome of a scene-stealing character, and Henry Winkler is great as the straight guy.

The Girl Next Door - the movie that launched Emile Hirsch, and an unfortunate victim of bad advertising from Fox, as it's a teen sex comedy that actually has heart. LOVE James Remar and especially Timothy Olyphant's Sid Vicious-coiffed porn mogul. The part where he warns a classroom of students to stay in school is priceless. Also features one of the best get-rich-quick schemes of all time.

Something Wild - the manic stepbrother of Scorsese's After Hours, instead of the night from hell it's the road movie from hell. And Melanie Griffith is super :drool: in this.

Any additional ones?

"Something Wild" was the first title that came to mind. Very good call. I'd like to add:

"Three O'Clock High"

"About a Boy" - Although highly rated by critics, only did 40m at the U.S. box-office. I thought it deserved such a bigger audience

"Married to the Mob" - Another Demme gem

"Clockwatchers"

"The Daytrippers"

"You Kill Me"

"Starter for 10"

"Drop Dead Gorgeous"

"In Good Company"

"Slither"

Heavyweights (1995)

Outside Providence

Absolutely. It's one of my favorite films from the 80's. Great stuff.

I'll add:

Meatballs
Serial Mom
Three Amigos
Swimming with Sharks
My Bodyguard

Accepted
Girl Next Door
Waiting
Grandma's Boy
Saving Silverman

What Planet Are You From? - I really wish Shandling would star in more movies.
Dirty Work
Almost Heroes
Multiplicity

Pecker
BASEketball
Ghostbusters II
Smiley Face
The Life Aquatic
The Ruling Class
Night On Earth
The Ladykillers (Hanks/Coen Bros. Version)
Freddy Got Fingered
Gigli
Stuck On You

Throw Momma From the Train
Dirty Rotten Scoundrels

I'll second this. I saw it for the first time earlier this year and enjoyed it immensely, which came as a nice surprise since I'd watched Roxanne a few days prior and hate, hate, hated it.

<b>SERIAL</b> - just released recently on DVD, this is a terrific comedy about flower power, California, cults, and sex. And you'll see a side of Christopher Lee that never showed up at Hammer.

"Top Secret!"

"Zero Effect"

"Grandma's Boy"

and kind of "The Ringer" had the Farrelly's had the balls to be offensive.

Bananas
Volere volare
Hangin' with the Homeboys
Gas-s-s-s
Meet the Applegates

Pretty Persuasion

That's exactly what I was going to say. Not only is it funny, but it's pretty touching in parts, such as the "coin collection" scene.

I've been watching the dudley moore 80's comedies lately, all are pretty underrated

I know the Maltin book gives it a bomb, but Scavenger Hunt is one of the funniest films I've ever seen. A great ensemble cast. My favorite bit is when Roddy McDowall, Cleavon Little and James Coco are stealing a toilet and are confronted, one of them replies "We have to check the timing in the turbo flush!" HA!

Used Cars - some of the biggest laughs I've ever had watching a movie (...and I knocked them motherfuckers right on their ass too)

Bowfinger - the ONLY multiple character Eddie Murphy film in the last fifteen years that's even remotely funny to me. And he's brilliant in it. Keep it together.

The 'burbs. One of my favorites of all time.

Rick Ducommun really deserved to be a star after that movie. He's perfect in it.

Both of those are great.

The sabotage of the football game in Used Cars is priceless. And yes, Bowfinger is the last great effort for both Murphy AND Martin.

Also second Three O'Clock High (what if John Hughes made After Hours?), Bananas, Dirty Work ("You bet on the fight in Rocky III!?"), and Zero Effect, another recent Netflix choice. Stiller needs to do more seriocomic stuff like that.

A few I wanted to amend to my list:

I completely forgot two Bill Murray films last night that I can't believe has evaded mention as of yet. First, Quick Change. Easily my favorite comedic performance from Murray after Ghostbusters and Rushmore, and infinitely quotable ("You're becoming Ralph Kramden's evil twin!"), plus hilarious supporting turns from Randy Quaid, Geena Davis, and Jason Robards as the cop who can't get a break. Plus Clarence Boddicker is in it! Other Murray film: Scrooged, one of the most mercilessly underrated Christmas movies of all time, which my friends and I all consider a perennial holiday film.

Bulworth - didn't appreciate it when I was younger, but holy shit this movie is hilarious. The idea of Warren Beatty as a politician using rather wrong methods to reach out to voters, doing weed and coke, rapping about his proposals, and bringing buckets of KFC to functions alone is hilarious, but Beatty completely kills it here in the lead. Oliver Platt is hilarious too. Also had an AWESOME poster.

EDIT: Can't believe I missed Night on Earth being mentioned. The NYC segment with Giancarlo Esposito and Armin Mueller-Stahl is hilarious.

My Blue Heaven with Rick Moranis and Steve Martin -- what's not to love about a comedy sequel to Goodfellas, about Henry Hill's life in witness protection?

<object width="425" height="344"><param name="movie" value="http://www.youtube.com/v/KZQSo5VCJic&hl=en&fs=1"></param><param name="allowFullScreen" value="true"></param><embed src="http://www.youtube.com/v/KZQSo5VCJic&hl=en&fs=1" type="application/x-shockwave-flash" allowfullscreen="true" width="425" height="344"></embed></object>

Champagne For Caeser(1950) Vincent Price is a riot!
The Hot Rock
Cold Turkey
Kiss Me Stupid
Ruthless People
Love At First Bite
Every Which Way But Loose