As others have said, look into real estate investing. Heck, maybe even look into getting your real estate license if you want a change. I wish I would have bought a duplex years ago, living in one side, and renting the other side out. Theoretically, you want to get a good enough deal that the renters in one unit pay all of the mortgage, taxes, and insurance so that you can live rent free in the other unit while building up equity in the duplex.
There are lots of books and websites out there to learn from. I don't know if I can mention any sites names without getting in trouble with the moderators, but try googling investment property education if you want to learn more.
As with any path you decide to take, educate yourself as much as possible before making any big changes.