Programming Challenges - A List
Lets start a list of programming challenges, and include a difficulty level for each program(easy, medium, or hard). Basiclly, you need to say what the program needs to do, any special features, whatever. Please post your files as an attachment, or host it and put a link to it, so to not spoil the answers to other people. Anyone can compete, and you could use any programming language you want, but since this is a C Programming Forum (well, it is Unix, but whatever), preferably C.
This should not be an epic failure,
Octal.