I've been part of a startup that has so far done nothing or gone anywhere in almost a year. I have pretty much given up on the place but I am curious if I can walk out with an game pitch I created. I developed the game idea and documentation long before ever joining the startup and introduced it as an option to showcase to potential investors in an effort to bring in some cash flow. Now I'd like to leave with it again. Is this possible to do in California? I am under a work for hire NDA but again with no pay involved.
Many NDA's and Confidentiality Agreements that I've signed have made a point to allow usage and continued ownership of information, ideas, and concepts that were created prior to the agreement by the individual who brought them.
Also, a major consideration is whether or not you'll be directly competing with the company if you were to go into business on your own. If it's possible that the company feels that, they'll be better off suing you then letting you start your business, then it's important that you know your legal obligations to them before getting started.
If there is very small to no chance that the company will be interested in the space you plan to move into then you'll be taking a much smaller risk by trying to start something of your own.
Regarding the question of sweat equity and ownership, California law states that any software developed by an individual is owned by that individual unless explicitly stated by a formal written agreement. In that case that you've developed any code before working with this company, you'll have strict rights to that code if you didn't sign those rights away.
However, as Joel says, you should update your question for more accurate answers and it's always best to consult an attorney at the end of the day.