The Mentalist 10 p.m., Channel 4
This repeat of the first-season finale finds the writers diving into the Red John mythology big-time. The guy - or gal? - killed Patrick Jane’s wife and daughter, and now he or she is trying to lure Jane back into his or her web. Don’t expect to find out Red John’s identity in the near future. Creator Bruno Heller told the Globe he won’t solve the Red John mystery until the end of the series, and “The Mentalist’’ is a ratings hit that will probably have a long life.
Samantha Who? 8 p.m., Channel 5
ABC is burning off the remaining episodes on Thursdays, beginning tonight. The Christina Applegate series not renewed for a third season, so it’s time to pay final respects. John Taylor from Duran Duran guests in this episode, as a former rock star who dates Samantha.
Burn Notice 9 p.m., USA
Michael infiltrates a gang. Can’t they see the sparkle in his eye?
River Monsters 8 p.m., Discovery Channel
Sharks that live in freshwater. Ah, blood pressure issues.
Demetri Martin. Person. 9 p.m., Comedy Central
Listing. Critic’s Corner.
Paint Misbehavin’ 10 p.m., TLC
Who cares what it’s about.
Extreme Pig Outs 9 p.m., Travel Channel
Once, a whole box of Trix, dry. I swear.