It's appeal is the interesting dialog and good acting by Page.

Rating: Null/10 (11 May 2008)

It is easy to see why Canadian Ellen Page received a best actor nomination for her role as Juno MacGuff. She plays a very self-assured teenager who finds herself pregnant. What she does with that situation is the interesting part of the movie. The writing is what makes this such a charming movie. Although, I hope that some teenage girls don't get the idea that having a pregnancy then finding a home for your baby is something simple and easy, to the point that they don't need to worry.
The movie was shot in Canada, and the boyfriend is played by another Canadian, expertly, by Michael Cera as the studious and nerdy Paulie Bleeker. Allison Janney is good as the mom, Bren MacGuff, and J.K. Simmons is good as the dad, Mac MacGuff.
As the story unfolds, and Juno rejects her first thought, to have an abortion, she finds seemingly ideal parents in Jennifer Garner as Vanessa Loring and her husband Jason Bateman as Mark Loring. But all does not go smoothly.
SPOILERS: After the interview and signing a contract, it becomes apparent that Vanessa really, really wants the baby, but Mark has very cold feet. Part of that is caused by his becoming distant from Vanessa, developing into their intent to divorce. This shatters Juno's ideal, wondering "why can't people stay together?" Still, in the end Vanessa as a single parent adopts the baby and all will end well. And, Juno finds out that she really cares for Paulie.
Sept 2012 edit: Just saw it again, still an excellent movie, good to re-watch every 2 to 4 years.