Tuesday, Oct. 18
6 p.m. “Firehouse USA: Boston”
The crew grows antsy after a long period with no fires. When they start handing out matchbooks at playgrounds, check the battery in your smoke detector. Discovery Channel
6 p.m. “40 Greatest Pranks”
We’re assuming these are celebrity pranks and not the really good ones like the Crusades and “Saddam’s Weapons of Mass Destruction.” VH1
8 p.m. “Supernatural”
A shapeshifter begins adopting the guise of others and committing murder. Now all we need is a shapeshifter who will visit the in-laws for us. WB
8 p.m. “Sex, Love & Secrets”
Jolene wants to make Charlie the next big celebrity hairdresser. This is a complicated process and requires a star-packed client list, a flamboyant personality, great locks and the kind of unmitigated enthusiasm for hair care rarely seen outside a junior high school girl’s locker room. UPN
9 p.m. “Close to Home”
Investigators uncover a prostitution ring of soccer moms. Come tomorrow, there will be a lot of PTA fund raising committees re-thinking the bake sale idea. CBS
9 p.m. “The Unexplained”
Tales of people who survived in the open water remind us that your seat cushion can be used as a flotation device but it is not equipped with cup holders or little umbrella drinks. Biography Channel