Elon Musk appears to be planning a restaurant or restaurant chain as his next entrepreneurial venture. Last week, Tesla filed an application to trademark its "T" logo with the identification "Restaurant services, pop-up restaurant services, self-service restaurant services, take-out restaurant services," along with filings for the word "Tesla" and its distinctive lettering of the word. The top-selling electric car maker in the U.S. just took a first step toward launching a fast-food business.