Try Matasano's Microcorruption CTF. It is designed for people with no experience. You will do the same things the author of the post did.

uctf strips away the layers of complexity related to a specific environment, giving you a clean place to learn the first principles. Whereas, if you tried this on a Gameboy, you must learn a lot of domain specific things, and learn how a computer works at a rather low level. For example: once you have built an exploit payload or two, it isn't so magical how using an inventory of items that are represented with integers can become code.