Well, it's mid-summer now, and hopefully all of you are in the midst of reading projects of your own (I certainly am . . . and everyone I know of is, as well). As far as a group book goes, however, I would like to make the following suggestion:
The Once and Future King by T. H. White (be sure to read the excerpt and this description of the book/series).
Within this volume are four books: "The Sword in the Stone," "The Queen of Air and Darkness," "The Ill-Made Knight," and "The Candle in the Wind." (The first book is the only one I've ever seen published alone.)
I also recommend you read the fifth book, which was published after White's death, and which I have never seen included in the single volume collection: The Book of Merlyn (synopsis here).
This is my favorite version of the Arthur legend (with Lawhead's version as a close second). It is fun, quirky, light reading and is full of hilarious and memorable scenes and quotes, but it also contains a good deal of depth and covers many important themes which are worthy of discussion . . . Clearly the perfect recipe for an SC summer book.
If you're on campus, I own a copy of The Once and Future King, and both that book and The Book of Merlyn can be found in the LeTourneau library.