My girlfriend loves The Chronicles of Narnia by C.S. Lewis. As a result, I decided to discover just what I'd been missing out on my entire life. I had read The Lion, the Witch and the Wardrobe a few times, but there were six other novels to explore. One month later, I have finished the entire series. Clearly to finish six novels in four weeks speaks to the quality of this series - or at least it speaks to my opinion of the quality of this series. After a month bouncing around Narnia, exploring Calormen, sailing to the ends of the ocean, burrowing into the Underland, and soaking up various other adventures, I have fallen in love with The Chronicles of Narnia as well. I'd go so far as to say this series is literary genius - compelling plots, witty narration, endearing characters, imaginative setting, and worthwhile lessons. If you haven't read these books, I'd recommend them. Beyond The Lion, the Witch, and the Wardrobe, my favorite was The Voyage of The Dawn Treader.
To rescue some of my coolness here, I've added SNL's take on the Chronicles of Narnia below, which I also love.