The Lifeboat Clique by Kathy Park

When an earthquake and tsunami hit an illegal high school party in Malibu, it decimates the house and the attendees. Later, a few kids cling to a chunk of debris floating in the ocean - including one very unpopular girl. What's worse: being lost at sea, or being shunned by the cool kids WHILE you're lost at sea?

Denver and Abigail used to be best friends, but now Abigail's popular and Denver is a pariah (we don't find out why until later, but it's easy to see it's the typical high school falling out). While the group drifts at sea, it's Denver's practical skills that allow their survival, but even that isn't enough to win over Abigail. It's hard to ignore someone in such a small space and under such harsh conditions, but Abigail's sure making the most of it.

It's a good book, and it moves quickly despite the harrowing situation. There's a bit of a "moral" but it's not too preachy. The characters are recognizable as the typical high school clique but still have depth and interest.

Nation by Terry Pratchett

The big wave took everything Mau has ever known - his Nation (a tropical island) has been swept away, along with all its inhabitants. The young man lived only because he was on the water when it happened.

The same wave killed everyone aboard a large sailing ship - except one properly raised "princess" ill-equipped for primitive survival. Against the odds and a language barrier, together they survive, grieve, grow, learn to communicate, and build a new Nation with the refugees who appear one by one on the island.

As with any Pratchett book, there's a lesson, some philosophical questions to ponder, and a lot of just really funny gags. This one pokes fun of monarchy and manners, introduces us to the tree-climbing octopus, and introduces a new brand of Robinson Crusoe.