Please recommend...

[shiznitz]

...a good movie for a group of 6th grade boys.  'R" rated is out and minimize love scenes, please. Just fishing for ideas.

[Paelos]

Goonies.

[Trippy]

Stand By Me.

[Shannow]

The Matrix (or is that too violent?)

[Father mike]

Despicable Me (first one)
How to Train Your Dragon
any/all of the Marvel movies (assuming none of the parents have issues with fantasy violence)
Raiders of the Lost Ark (was PG, right?)

[shiznitz]

The Matrix (or is that too violent?)

Borderline but I like it.  I even have it on DVD somewhere.

Keep them coming.

[Kail]

You could always fall back on Disney if you're worried about content (they did some stuff around 2000 that was more for that age range, Treasure Planet and Atlantis and so on, maybe The Black Cauldron though that's a bit dated).

Pixar would probably work, too.  Incredibles would be my personal choice, but the kids I'm working with love watching "a Bug's Life" over and over again for some mystifying reason.

[Rasix]

Princess Bride
Any Lord of the Rings movie.
Jurassic Park
Serenity
Monty Python and the Holy Grail (maybe not yet)
The Fifth Element
Army of Darkness

[Paelos]

Twister, because it's silly and fun.

[Abagadro]

Avengers is one of the more reasonable PG-13s of recent memory.

[Signe]

Absolutely go with Goonies.  Tres awesome.  How old are you in 6th grade?  Like 12, right?  GOONIES!  And it's old enough that they might have never seen it. 

[Venkman]

Yea for modern: Avengers.

In general though:

Goonies on top of the list- fun, adventure-y, kid appropriate melodrama
Back to the Future- aspirational everyman lead with quirky science stuff
The original Star Wars- get them started the right way
Toby MaGuire Spiderman- safe-ish except for the father killing thing

[Miasma]

A lot of these are movies we would/did like in the 6th grade, I don't know if those would have any appeal to current kids.  I sure as hell wouldn't have wanted to watch whatever my Dad liked when he was in 6th grade.  Probably something horrific, with singing in it, like Mary fucking Poppins.

[Yegolev]

Everyone posting in this thread is fucking old.

I have a fouth-grader so I really have little idea.  Jurassic Park is on the right track, I think, if from the wrong millennium.  Might as well suggest a series of On The Road movies, which are good but probably not popular with sixth-graders.

Any of the better Marvel movies could work; the fourth-graders liked the second Thor even if they didn't really understand what was going on.  I heard the second G.I. Joe was very watchable.

The first Cloudy With A Chance Of Meatballs was far better than it had any right to be.  The second Cloudy is out now.  I haven't seen it yet but it's waiting on the shelf, ready to put me in a food-pun-coma.

[Signe]

You're old too.

[MisterNoisy]

If you have Amazon Prime and you and your audience isn't averse to animated stuff, there's a ton of DCU content via streaming, most of which is good fun and included with Prime.  Green Lantern: Emerald Knights is a solid watch and has the advantage of being a collection of vignettes inside an overarching plot, so sixth-grade attention spans won't be challenged.

[Shannow]

A lot of these are movies we would/did like in the 6th grade, I don't know if those would have any appeal to current kids.  I sure as hell wouldn't have wanted to watch whatever my Dad liked when he was in 6th grade.  Probably something horrific, with singing in it, like Mary fucking Poppins.

As the father of a 7th grader I can tell you you would be surprised how much they like stuff from our era. My boy LOVES Back to the Future. Him and his friends thought the Matrix was very cool (yeah I let them watch it, I still think it's on of the best scifi movies of the last 20 years, one of the last movies that genuinely made me go 'woah').

Also Karate Kid, old and new.

[murdoc]

When I was in grade 6 I was watching the Friday the 13th and Nightmare on Elm Street movies.

[Paelos]

The first Pirates of the Caribbean.

[Sir T]

The first 2 Chris Reeve Superman movies are still fairly decent.

The Hunt for Red October, the least violent action movie you can get, and it still rocks.

The Rock is a good entertaining movie but it has scenes of guys getting gunned down.

The Abyss is great till you get to the last quarter of the movie where it falls to bits.

Casablanca. You might as well hit them with the best when they are young.

Mel Gibson's Hamlet if they are doing Shakespeare in school. Its genuinely a great adaption.

The Land Before Time. Good animated movie and they wont have seen it.

Some of the Star Trek movies are pretty decent, namely 2, 3 and 6. 4 is good fun but its really an excuse for the characters to ham it up. But they will enjoy those 3 at least.

Beauty and the Beast. Its a genuinely great Disney movie with none of the Disney crap.

"The 7th Voyage of Sinbad" from 1958. One of  Ray Harryhausen's finest works.

The Black Stallion.

If you are seriously demented then you could try "The 5,000 Fingers of Dr. T"  Its Doc Seuss's only screenplay and it's, to put it mildly, a bit weird. Great fun though. It also includes the line ";Is it atomic?' 'Yes! Very atomic!'" which is worth the price of admission.

[Samwise]

Monty Python and the Holy Grail (maybe not yet)

I got my first exposure to Monty Python in 6th grade via Holy Grail.  Our class pet was a white rabbit and our teacher made an offhand comment once about it looking like the killer rabbit from Monty Python.  When we all looked at him blankly, he was horrified and brought the movie in so we could watch it in class.

In retrospect as an adult that's kinda lolwut, but for obvious reasons he was far and away my favorite grade school teacher.   

[Chimpy]

Avengers is one of the more reasonable PG-13s of recent memory.

And Uma Thurman is smoking hot in patent leather! 

(Yes, yes. I know you mean the one with all the comic book heroes.)

[Signe]

The Hunt for Red October?  Casablanca??  Huh?  Twelve years old!    HAMLET!  Wot?

[01101010]

As strange as it may be, what about John Carter?

Then again, I know nothing of kids so I can't gauge what is too violent.

[Paelos]

Big Lebowski. 

[TheWalrus]

Tron Legacy

Because the lil bastards won't appreciate Tron.

[Venkman]

Let's make no mistake. If you're responding, you're ALL old 

A lot of these are movies we would/did like in the 6th grade, I don't know if those would have any appeal to current kids

Come come, I wouldn't recommend them if my kids' friends hadn't seen them.

Of course, in my household it's all Radio Rebel and the High School Musicals. I mean holy shit... who the fuck is going to be recommending that crap to their kids in 30 years after they're remastered for the 50th time at holo12K resolution or whatever? They're barely palpable without serious adult beverages. I can watch Phineas & Ferb and Penguins of Madagascar by the season. But, yeesh, well, my parents probably felt the same about Better Off Dead or 16 Candles I guess.

[Goumindong]

...a good movie for a group of 6th grade boys.  'R" rated is out and minimize love scenes, please. Just fishing for ideas.

Things not mentioned

Big Trouble in Little China
Hellboy
Star Trek: The New One
Clue
Shaolin Soccer
For a Few Dollars More (Once Upon a Time is PG-13 and harder to digest, but no more or less violent so i can't see For a Few Dollars More having any issues)
Butch Cassidy and the Sundance Kid

Definitely going to second "The Princess Bride", "Back to the future", "Jurassic Park"

[ezrast]

I don't know anything about kids but I'd be surprised if there is a more correct answer than The Princess Bride.

[Merusk]

Explorers   

Flight of Dragons
The Last Unicorn!

[Soln]

Time Bandits

[Signe]

No, not Time Bandits.  Children don't want their parents to be burnt to crispy black lump of coal until they're 14.  Sometimes 13 if they're precocious.  Hellboy was good fun and Big Trouble in Little China was a riot.  Okay, now I have to make a list out of all these suggestions to watch myself again.

[SurfD]

Flight of the Navigator

[Viin]

Princess Bride

[apocrypha]

Lord of the Flies.

They're 12, not 7.