"The Bitcoin Entanglement" -- Pictured: Sheldon Cooper (Jim Parsons), Leonard Hofstadter (Johnny Galecki), Amy Farrah Fowler (Mayim Bialik) and Penny (Kaley Cuoco). Sheldon tries to teach the guys a lesson after they cut him out of a potentially valuable Bitcoin investment. Also, a seven-year-old video reveals a secret about Leonard and Penny's relationship, on THE BIG BANG THEORY, Thursday, Nov. 30 (8:00-8:31 PM, ET/PT) on the CBS Television Network. Photo: Michael Yarish/Warner Bros. Entertainment Inc. ÃÂ© 2017 WBEI. All rights reserved.