Elon Musk is getting ready to announce a new product -- but he's not giving many clues about what it might be. On Sunday morning, the Tesla CEO sent out a tweet about a "product unveiling" on Oct. 17. So what is this new Tesla product, which, according to Musk, will be "unexpected by most?" SEE ALSO: Elon Musk: Is his Mars Shot impossible or inspired? Is it a new Tesla model? While that product might be a mystery, it's pretty clear that Musk will reveal a new solar rooftop at the Tesla/SolarCity event on Oct. 28.