I've collected all my reverse engineering challenges/exercises/problems/tasks at the stand-alone website: //challenges.re/. 73 so far.
The website has been inspired by Project Euler and "the matasano crypto challenges".
Stay tuned, more exercises is to be added...
Some discussion: hacker news; reddit; Czech forum; http://www.forumcrack.com/viewtopic.php?f=13&t=13341.
→ [list of blog posts, my twitter/facebook]