About ¾ of the way through Pixar's Up, Russell, the main child character, says something that sums up the whole movie very nicely.  I wish I could remember it verbatim, but I can't.  And I can't find it on the web, either.  So here's my best attempt.  He says:
The wilderness is a lot different than I expected.  It's a lot wilder than the books made it sound.

Up reminds us that it's not just the wilderness that ends up being different and wilder than we expected; it's all of life.  The two main characters can testify to this.  Carl has recently become a widower.  The first ten minutes of the film chronicle his relationship with his wife, Ellie.  It makes for a beautiful movie within a movie.  Russell is a boy growing up with an absent father.  (Are his parents divorced?  I can't remember.)  Both people are coming to grips with all of the ways that life has tossed them around and dashed their expectations.

Be warned, if you're prone to crying at the movies, bring some tissues for this one.  There are Bambi's mother/"Baby Mine" from Dumbo kinds of sad moments.  I asked my 3 year old if he liked the movie and he said, "Yeah.  It made me sad."

But please don't let me scare you away.  The other message of Up is that grace also comes in wild and unexpected ways.  One of the great joys of watching it is getting to see how these two people who are suffering their own losses find new life together.  (I can't imagine that I'm ruining the movie by telling you that it has a great, great ending.  It is, after all, Disney.)  With them, we learn that good things happen if we can let go of the plans we have made and embrace the unforeseen.  One scene illustrates this really well, but I don't want to ruin the surprise.

As a Christian I can't watch it without remembering how Paul says "No eye has seen, no ear has heard, no mind has conceived what God has prepared for those who love him (1 Corinthians 2:9)."  Or how he reminds us that God is capable of making something good come out of even the worst events of our lives (Romans 8:28).

Deep thoughts aside, the movie is a lot of fun.  Be prepared to laugh hard every time Dug the talking dog or any of his counterparts shows up.  And, once again, the artistry is stunning.  I could watch the balloons in all their translucent wonder all day long. Or I suppose I could blow up a real balloon and watch it.  Isn't it funny how good animation can remind us that there is beauty in the mundane?