I came across this site techinterview.org that lists many of the tech interview puzzles that you may encounter sometime in your career path. For me being a puzzle lover, this site is awesome! I hope you like it as well!
If you are looking for some more intense technical interview questions, here is another website you may want to check out: techinterviews.com. Notice that there are many questions on this site, but you need to find the answers yourself… ^^;