This was not the case in my experience at Google. It heavily depends on your specific group, project, and direct management hierarchy. Eg they might let you wo

This was not the case in my experience at Google. It heavily depends on your specific group, project, and direct management hierarchy. Eg they might let you work on some open source project, but if you wanted to commercialize some side project, it's an entirely different can of worms. (And different clauses I'm your employment contract.)