If you think that challenges to books by people you actually know are unlikely, I'd encourage you to take a second look.
Here are challenges of which I am aware from 2008 and 2009 to books written by people whom I know in real life:
Looking for Alaska was challenged in February 2008 at Depew High School outside of Buffalo, New York. The challenge was made by community members, who had the temerity to use the word "pornography" in describing John Green's novel. You can read my post from back then, "John Green is not a pornographer", which includes John's vlog post, "I am not a pornographer". That challenge was unanimously shot down by the school board. Alaska was one of a number of books challenged by a group calling themselves "Citizens Against Pornography" in the St. Louis County Libraris in St. Louis, Missouri. The group asked that the library impose restrictions on the books, such as using a “rating” system to classify books, or requiring that teens get written permission from a parent or guardian to check the books out. I'm not positive what the outcome to that particular challenge is, although I know that the National Coalition Against Censorship and the American Booksellers' Foundation for Free Expression sent letters opposing the action in St. Louis. Alaska, along with An Abundance of Katherines, Paper Towns and Let it Snow and at least 36 other books, is facing a current challenge in Leesburg, Florida, with a coalition of two mothers and whoever they could stir up claiming that the books are "vulgar".
You can read more about it in John's blog post from yesterday and in Leila's excellent post at Bookshelves of Doom, with lots of linky-links to give you all the background and context. It appears that the issue is resolved (at least temporarily) by the creation of a specific set of book shelves for "high school" books, which would include all of the books being challenged (and more). The proposal to establish the separate shelving area came from the library itself, and will mean no books are actually removed from the library, as I understand it. On a practical level, it will likely mean that access to the books isn't impeded either, which is as it should be, but not as Dixie Fechtel, book banning crusader, would like it to be.
Speak and Twisted by Laurie Halse Anderson underwent recent challenges. Twisted was challenged in Downingtown West High School in Downingtown, PA, but the involved teachers were able to reach a quick resolution with the teacher, where Twisted was on the summer reading list. Twisted was also challenged in Montgomery High School in Mount Sterling, Kentucky. Speak was challenged in Temecula, California, where a parent called the book "smutty" and "pornographic". (Again, a challenge to a book that discusses rape based on it being sexual, rather than violent, one of my personal hot buttons. Rape is not sexual, although it includes actions that involve sex. Rape is violence and aggression and hostility. And if it appeals to one's prurient interest (the definition of pornography), then one has a decidedly warped sensibility. I'm just saying.) All three attempts to ban those books were shot down.
Lessons From a Dead Girl by Jo Knowles faced the same challenge as Laurie Halse Anderson's Twisted in Mount Sterling, Kentucky. While Jo's book has survived the challenge, along with Laurie's and books by Chris Crutcher, Neal Shusterman, Sheri Reynolds and Sonya Sones. Only three of the seven books pulled from the classroom had the appropriate paperwork filed, and all three (Twisted, Lessons and Shusterman's Unwind) survived the challenge, although it's not clear whether they've actually been returned to the classroom shelves yet.
Think the Mount Sterling issue is over? Think again. As Laurie Halse Anderson posted today, the teachers in Mount Sterling have been reprimanded for wearing T-shirts bearing the quote you see up above to the left there from To Kill a Mockingbird. The reason? The administration said it constituted political activity. On the one hand, the administration is correct. But I think it still falls under First Amendment protected speech. I wonder if they'll file a grievance . . .