Sleeping at the office is nothing new for Elon Musk. The self-made billionaire CEO of Tesla and founder of SpaceX famously burns the midnight oil at his Tesla factory. Musk told "CBS This Morning" host Gayle King in April that he sometimes sleeps on a couch in a conference room at the Fremont, California factory as he tries to avoid any further delays and missed production targets for the Model 3 electric cars. But Musk is no stranger to the office couch. In the '90s, before he struck it rich as an entrepreneur, Musk had to sleep at the office because he couldn't afford an apartment. "When my brother and I were starting our first company, instead of getting an apartment, we just rented a small office and we slept on the couch," Musk said in a 2014 commencement speech at the University of Southern California.

That first company went on to become Zip2, a web software startup that created online city guides for newspapers. Musk and his younger brother, Kimbal Musk, founded the company in Palo Alto, California in 1995 and eventually sold it to Compaq for roughly $300 million in 1999. Musk used the money from that sale to found X.com, the online financial services service that merged with Confinity in 2000 and later became PayPal. But before Musk and his brother could cash in on their first big venture, the bootstrapping brothers had to rough it by living in their small office. "We showered at the YMCA and we were so hard-up that we only had one computer," Musk said in 2014. "The website was up during the day and I was coding it at night, seven days a week, all the time." "I briefly had a girlfriend in that period and in order to be with me she'd have to sleep in the office," Musk added.