“Cash Cab” is a addictive game show that takes place in a New York City cab. A British import, televised by the Discovery Channel (10 a.m., 10:30 a.m., 6 p.m., 6:30 p.m.), it’s become a word-of-mouth hit. People enter the Cash Cab, expecting to go for a taxi ride… only to discover they are instant contestants. Comedian Ben Bailey, the likeable host and driver, explains the deal. The riders answer questions until they get three strikes or arrive at their destination.