OK, So, a while ago i was reading something about race conditions. Where a user can beat a suid program to a file or could also be used to run another suid program. Is that correct? also that file i was reading had an example of how to create a race condition. I have been wanting to learn about security and my ultimate goal is to set up my own computer where users can 'level up' by hacking their way through. I figure this would be a good way for me to learn and then be able to teach others about it.

So, can anybody point me to where i can find out about race conditions, or a list of kinds of security flaws that i could build my 'levels' with. I have a hard time finding good security sites.