Since this forum is deader than a funeral I figured I'd start posting some information on 3.0 + 3.5 books that are entertaining and pretty cheap to get a hold of now a days. Today's books is one of my favorites and probably one of the best reference books you'll find for challenging encounters in dungeons and pretty much any scenario!
(http://ecx.images-amazon.com/images/I/51XSGF9YA7L._SL500_BO2,204,203,200_AA219_PIsitb-sticker-dp-arrow,TopRight,-24,-23_SH20_OU01_.jpg)
The book of Challenges
It's basically a in depth look at puzzles, riddles, traps and other kind of dreary things you'd find in various dungeons / crypts / confined spaces. A lot of my adventures when it comes to dungeon crawling uses this book for the riddles and traps. Most definitely a great read and you can pick the book up from eBay for about 8$ + shipping. I do have an e Book of it in case anyone still running a game would like to take a peak at it. Even if you're not running a game any past player will cringe when looking at it, and it is a fun read.
I give it a 8 / 10
Great information
Easy to read
The only downside is it is a short book and the adventure spans aren't really setup for 1st level characters (though there are some pre made templates for it)