I read the Dressage Chronicles on my nook, and I read one of Bev Pettersen's track mysteries on there, too (have another one, just haven't started it). Jane Smiley has a few horse themed adult novels, and some kids ones now too! Scorpio Races by Maggie Stiefvater is supposed to be good.
The Oulander series by Diana Gabaldon...seven or eight BIG books, that should do it! Fun, fun read.
If that is not enough for you, The "Song of ice and fire" series by George RR. Martin is addictive as well!
Otherwise, in random order:
- Stephen King's latest book, 11/22/63
- Barbara Kingsolver The Poisonwood Bible (my favorite) but her other books are fun too.
- Horse Heaven by Jane Smiley
- Molok'ai ( I forget the author)
- The Glass Castle and Half broke horses by Jeannette Walls
- The Golden Compass trilogy by Philip Pullman (the movie did NOT do it justice at all)
- The Farseer trilogy by Robin Hobb was fun to read as well, if you like that genre (fantasy)
If you're interested in the Hunger Games, you might also like the Mortal Instruments and Infernal Devices books by Cassandra Clare. Start with "City of Bones" and "Clockwork Angel." Excellent, fast paced, good characters, well written YA urban fantasy.