The document most certainly said that my employer owned everything that I did that was related to my employer's business. The thing about working on salary is that there's no punching in and out; just because I'm working at home doesn't mean I'm necessarily "outside of work" -- I worked at home doing paid work for over three years, in fact, seeing the inside of their office only 2-3 days a month.

I work in games. If I do something in my free time that's game-related, it's arguably related to the work my company does.

So I quit and started contracting. Now I own what I work on when I'm on my own time.