I rather enjoyed the Fablehaven books. They are about a pair of twins (one girl, one boy) who spend the summer at their grandfather's nature reserve. The two don't understand any of the strange rules, such as don't go out at night, don't mess with any of the animals, and, above all, stay out of the woods. Nor do they understand where their grandmother is or what happened to her. Little do they know that this isn't just a nature reserve; it's one for enchanted creatures. Soon, they wil learn that the rules are there for a reason. But only once they're broken...

These books tend to end up at consignment/thrift stores for five dollars or less, which is how I managed to get the whole series. You can also find them at amost any local library, or even your friends' houses! I tend to read through them in about a day's time, because they have interesting plotlines and are just easy to read. Don't let their size intimidate you; Fablehaven is amazing!