You would have to show that anything non-work related which you produce existed in at least idea form before you signed this (by attaching it as 'Exhibit A'). Anything you don't declare up front belongs to the company for the duration, including your inspiration as soon as you commit it to tangible form. You could ask for a clause providing you with an opt-out mechanism for side projects you may come up with later, eg open source things you want to do for the public good or whatever. It's boilerplate, but it's very one-sided boilerplate. I wouldn't sign this unless I had equity.