22nd century Earth is devoid of green, and they've gone to a world called "Pandora" to mine an element called "Unobtanium". Pandora is a primitive, hostile world, with a lot of carnovores, and an indigenous humanoid species called the Na'Vi. The Na'Vi are a deeply spiritual people that would have made great Jedi Knights, believing that there is a Force that dwells in all of us -- that rock, that tree, etc etc. The secret to life is to "see" this connection among all living things.
Earth apparently has been totally run over by the Bush Administration, and instead of sending The Starship Enterprise to boldly go to Pandora, they send Vice President Cheney and a platoon of jar heads. George Bush apparently told them to disregard every lesson in history where an indigenous population is unjustly eliminated from the environment in order to fuel the unimpeded growth of the more powerful empire. Cheney (who now is a very beefy military guy with the stereotypical See The Hill Take The Hill attitude) sees no problem in conducting a bit of racial cleansing and genocide in order to get his hands on the Unobtainium. He doesn't even wonder why the hell anyone would call an element Unobtainium; doesn't even try to change it to Imperialuminum or Caucasionite or something like that.
The scientists have figured out a way to blend human DNA with the DNA of the Na'Vi, in order to produce beings that look like Na'Vi but can be controlled by a human. So they basically get into these tanning beds, and can hook up via bluetooth to their Avatars, where they can pretend to be the Na'Vi. But as anyone has witnessed watching any television, when you spend time amongst the Native Americans, of course, you are going to become a Native American. You give up your laptops, your machine guns, your cell phones, and you strip down to a jock strap, grow a tail, drop to 2% body weight, go barefoot, and start swinging on vines. That always happens whenever you live amongst Native Americans, and it happens when they start running around with the Na'Vi.
An interesting part of the story are all of the flora and fauna of the planet. The Na'Vi are blessed to live in a tropical rainforest, where for some reason, although filled with sunlight, many species of plant and animals have developed bio-luminescence. Even though bio-luminescence generally only develops in dark environments, like the deep ocean. So there are many beautiful plants and animals that glow, which really is quite beautiful.
Overall, I'd have to give Avatar 4 1/2 stars out of 5. I did find it very entertaining, although the "lesson" was a bit simplistic, with too many stereotypes. 99% of the experience for me was sensual -- the 3D thing totally works, and was used to imerse the audience in the environment. Not too many gratuitous scenes with sticks or tubes being shoved into your face. The heroes were all likeable, and the villains were easy to hate. Everyone was either a hero or a villain, pretty much color-coded by uniform.
Sigourney Weaver is pretty good in this movie. She sort of continues her "Gorillas in the Mist" experience but now has the advantage of saving the environment in 3D. She's a scientist, but unfortunately, she is outranked by a superior-ranking scientist who is more interested in corporate interests, even when that means a bit of ethnic cleansing. He's pretty much a re-incarnation of Weaver's antagonist in Aliens, then played by Paul Reiser. Sigourney even finds a new incarnation of the jarhead/hero then played by Michael Biehn.
In the end, the Na'Vi won. Cheney is disgraced. The Na'Vi go on to build a conglomerate of casino's, etc. No, just kidding, but it really is a feel good movie.
Be careful about bringing the kids. ALL of the indians are dressed in jock straps, cute animals are killed by the bad guys, and one horse-like animal is horrifically set on fire while still alive.