Xanth series by Piers Anthony
Each human character in Xanth is born with a unique magical ability, called a talent. In addition to the human characters, Xanth is populated by centaurs, demons, dragons, fauns, gargoyles, goblins, golems, harpies, merfolk, naga, nymphs, ogres, zombies, curse fiends, and other fictional beasts.
Geographically, modern Xanth resembles the real-life state of Florida. One major exception to this is the Gap Chasm, an enormous canyon a mile wide which completely bisects the country. Xanth has a connection with the normal world, which is referred to as "Mundania," its people are called "Mundanes". Although any citizen of Xanth can enter Mundania at any time through an isthmus in the northwest, Mundanes enter the isthmus in Xanth from random geographic locations and time periods throughout history.
The Adult Conspiracy is one of the prominent features of the Xanth world. Nearly every book except the very early ones contain references to the Conspiracy and its effects, particularly those novels in which the main characters are children. At its core, the Adult Conspiracy seeks to protect children from knowledge that could bring them to great harm. The precise age for entering into the world of the adults is age 18, corresponding to the age of majority in most places. The primary principle that inducts children into the Conspiracy is the understanding of the secret of "summoning the stork." In Xanthian terms, "summoning the stork" literally means to put out a call to summon a stork which will deliver to the couple a child. Other faculties of the Adult Conspiracy include censorship of foul language and the inability to have childish fun.
*Description taken from the Wikipedia entry for Xanth.
I discovered the Xanth series by Piers Anthony when I was around 12 years old. It was one of the first young adult/adult series that I read and once I discovered them, I read every novel in the series that I could get my hands on.
At the moment, there are 33 books in the series. The first book is A Spell for Chameleon. This introduces the magical world of Xanth and its magical human inhabitants, except for Bink, who apparently is without magic. Bink sets off to see the Good Magician Humphrey, who has a giant book of answers, to find out why he has no magic. Thus begins a fantastic and pun-filled adventure that sparked a wildly popular fantasy series!
When I started reading this series, though, I did not begin with the first book. I randomly picked up book 17, Harpy Thyme, and instantly fell in love with the characters and world. One of the great things about this series is that you CAN pick it up anywhere. Though there are a few themes that continue and develop throughout the series, each book basically stands on its own.
Each has a separate cast of main characters, its own series of puns, romance, adventure, and a satisfying conclusion.
Another thing that I really enjoy about this series is that it is fun and romantic, and sometimes a little wild, but without being outrageous or smutty! With the inclusion of the "Adult Conspiracy," Anthony guarantees that there are no gratuitous sex scenes and swearing is almost nil. There is a lot of suggestiveness, but a twelve-year old CAN read these books without being traumatized!
The newest book in the series is Jumper Cable. It is another fun addition to the series, though I personally was not fond of one of the characters, a wood wife, who spoke using "nature terms" throughout the book. For example, she would say "Yew look very nice today." I was constantly correcting the words in my head as I read them, so my brain began to hurt if I read for too long in any given sitting. Other than this character's speech pattern, though, it was another excellent Xanth book.
If you are looking for a fun and light read, try one of Anthony's Xanth books.