Will check out Project Euler... doesn't sound familiar.
Cool thing about a good game engine. You don't have to use it just for games. It just saves you having to do all the very complex building of a powerful and efficient 3D engine, and input handler. So you can focus on the fun stuff. Unless you want to build an engine. :) You can use the tech for anything though :)
EDIT: Project Euler sounds cool. I book marked it up. I'll keep in mind maybe posting something about old school computer stuff. I wouldn't have thought of that.