Overview: Silicon Valley venture capitalist, Chris Sacca, returns to the Tank as a Guest Shark. A husband and wife team has a device for babies to stay on track and parents to stay sane; entrepreneurial twins have an online business that can ease the pain of paying for college; and a man has a tech solution to the dreaded parking ticket. Plus, a follow up on Rugged Races, the events company in which Mark Cuban invested during Season 5.