"Ender's Game" by Orson Scott Card

Ender Wiggin is an extraordinary game player. His brain is so sharp and brilliant that he's been chosen to attend a prestigious Battle School, where students are trained in military combat. It's the future, and planet Earth is preparing for an invasion against the buggers - alien lifeforms that are determined to destroy our planet. Using high tech computer games to simulate fights and battles proves to be intense and exhausting. Every move Ender makes must be perfect, the future of the universe depends on it! Great science fiction writing.

"Mister Monday" by Garth Nix

This is the first book in Nix's new series - "The Keys to the Kingdom." After nearly dying from a bad asthma attack, 7th grader Arthur is saved by a key shaped like a minute hand of a clock. Mister Monday is on a mission to get the key back. Arthur must venture inside a mysterious mansion, in which doors open onto alternate realms. The prophecy of The Will must be fulfilled and Arthur has been chosen to determine the fate of the universe. This is a great book for any fantasy lover - suspenseful and creepy!