Over at Locus Magazine, there's a great post full of sci-fi recommendations for young people written by Karen Meisner, an editor over at Strange Horizons (disclaimer: Karen and I have "known" one another online for...ever.) It's such a great idea I wanted to add some of my own.
SPACEHEADZ! by Jon Scieszka: I just spent three days with Mr. Scieszka, driving him around to five school visits and a library event, and I have to tell you - there is nothing more likely to re-inspire a children's book person like spending three days with Mr. Ambassador. Having book talked SPACEHEADZ about 25 times at 5 different schools, I can say that I am extremely familiar with this series - and I LOVE it. It's about a boy named Michael K who is starting at a new school, super nervous about fitting in and making the right friends. And who are the first two kids he meets? Bob and Jennifer, who tell them that they're aliens, and that their leader, Major Fluffy, is disguised as the class hamster. They're there to get 3.14 million + 1 Earthlings to sign on to be Spaceheadz, or their planet will shut Earth off. They're on the run from the AAA (the Anti-Alien Agency, natch) and need Michael K's help. (His response? "Please don't sit next to me.") It is awesome; perfect for reluctant boys especially, and very interactive. There are several related websites and an iPhone app I love called FLUFFY SPEAKS, where you can translate any language into Hamster.
ALIENS ON VACATION by Clete Barrett Smith: I was thrilled when the rest of the New Voices committee agreed with me about this one, too. Scrub is forced to go stay with his grandmother for the summer, but everything changes when he learns that the B&B she runs is actually filled with portals to other planets, and she plays hosts to aliens who want to spend their vacations on Earth.
IGNATIUS MACFARLAND: FREQUENAUT! by Paul Feig: I can never understand why this series hasn't broken out. I raved about this book back in 2008. For some reason the permalink to this post is being cranky, but if you go here and scroll down to 7/18, the review is there. I LOVE THIS BOOK.
SCIENCE FAIR by Dave Barry and Ridley Pearson: super funny story of aliens who trick not-so-smart arrogant rich kids into building parts of a superweapon for their science fair project (so the aliens can then use the weapon to take over the earth), and the brilliant middle-class kids who bring the whole plot down.
THE SEARCH FOR WONDLA by Tony DiTerlizzi: This beautifully illustrated novel tells the story of Eva Nine, a young human girl raised underground by a robot named Muthr. When her home is destroyed, Eva is forced aboveground where she learns that she is the only human on the planet. She must go on a quest to find others like her, and ultimately, a home.
THE CITY OF EMBER by Jeanne DuPrau: Electricity powers the city of Ember, and light ends at the city's edge. But the lights are starting to go out, and there doesn't seem to be any way of stopping it - until Lina and Doon find a mysterious document that might just show them the way to save everyone.
COSMIC by Frank Cottrell Boyce: 12-year-old Liam is tall enough to be mistaken for an adult, and cons his way into winning a contest to chaperone four other kids on a trip into outer space. What happens when the kids break the ship and look to Liam - the "adult" - to fix everything?
SIMON BLOOM: THE GRAVITY KEEPER by Michael Reisman": Simon stumbles upon the teacher's edition of his science book, which actually allows him to manipulate the laws of physics. Naturally, evil people seek said book, and Simon and his friends must keep it out of their hands.
KAPUT AND ZOSKY by Lewis Trondheim: graphic novel about two unbelievably incompetent aliens who make attempt after hapless attempt to take over the universe.
ASTRONAUT ACADEMY by Dave Roman: first in a graphic novel series about a former super hero who's just trying to blend in at the Astronaut Academy. If only it wasn't for the pesky robot doppleganger who's trying to kill him...
many books by Margaret Peterson Haddix: Haddix can satisfy many a yearning for this type of book. TURNABOUT; the SHADOW CHILDREN series; and THE MISSING series are all terrific sci-fi books for late elementary/early middle school-aged kids, and high level younger readers will love them too.