If you plan on commercializing those pursuits, talk to a lawyer before signing a contract. Most states/companies will give full ownership of all your work even on your own time to the company. States like California are more protecting of employee off time work but they still lean towards employers if your work "relates" towards your employer which for the top paying companies like Google/Apple/Facebook/Amazon/Microsoft is practically everything so you can still be screwed.
If you plan on commercializing those pursuits, talk to a lawyer before signing a contract. Most states/companies will give full ownership of all your work even on your own time to the company. States like California are more protecting of employee off time work but they still lean towards employers if your work "relates" towards your employer which for the top paying companies like Google/Apple/Facebook/Amazon/Microsoft is practically everything so you can still be screwed.