Aubrey surprises David Letterman when she reveals the story of the film she's in alongside Hollywood superstar Robert De Niro. The conversation then turns to drinking and the host talks candidly about his past.

Building something that works can bring a lot of satisfaction. In this case, it's building bikes. Paul likes figuring things out, and seeing what works and what doesn't. Together with a friend, he embarks on a challenging project: building an electric cargo bike!

Gwen Stefani talks about her Christmas album, You Make It Feel Like Christmas, and how Blake Shelton's adjusting to life as People's Sexiest Man Alive.

Paul goes into detail about what materials he used to construct the electric cargo bike. Some features turned out to be essential, such as the kick-stand.