I wouldn't sign that any more than I'd sign a contract that gave the company everything that I produce in my own time. Both are attempts by the corporation to dissolve my agency as a human being. The only right answer is no.
Such contracts ("produced on own-time belongs to company") are common at large software companies. If you are in California, such a contract may not hold water. Any one have experience with a big co (outside Cali) where they were able to negotiate this clause away?
I've found three good pushback techniques:
1. "My [insert family member] is a lawyer and I haven't seen this clause before, so I'm going to get her to read over the agreement." Next day I just say that they won't let me sign it. Why make up a family member as a lawyer? Because to push back or hire a lawyer is viewed as an aggressive move, while affably showing deference to your family member isn't.
Later in life when the job / contract offers started getting bigger:
2. "I don't sign things I don't intend to follow and I'm going to be building things in this industry on my own time for my own profit." Strait up confidence along with the fuck-you attitude to back it up by walking away. I'm never going to work for someone that is that dense and short sighted anyway.
Every single company has allowed me to just strike out the clause and have us both initial it.