“Nothing so concentrates one’s mind so much as the realization that one is going to be hanged in the morning.” So wrote 18th-century wit Samuel Johnson, and his words still ring true. The urge to savor every hour often arrives only when we realize that our moments are short. That’s pretty much the lesson and hook of the reality special “Live for the Moment” (7 p.m., CBS).

Jeff Probst hosts this hour-long testimonial to Roger Childs, a Colorado husband and father who discovers that he has been diagnosed with ALS (Lou Gehrig’s Disease) and given scant years to live.

As you might expect, “Live” does not dwell on the negative, but quickly whisks our hero through a series of once-in-a-lifetime experiences. All of this is both heart-warming and over-the-top, a strange example of how television can both elevate life’s dramas while at the same time reducing everything it touches to mere television. It’s a Make-A-Wish experience presented with all the solemnity of “Let’s Make a Deal.” The show adds an odd new twist to the old saying “dying to get on television.”

Or maybe not so new. In the 1937 comedy “Nothing Sacred,” Carole Lombard portrays a Vermont maid embraced by New York City’s media elite after she convinces them that she has mere weeks to live. That movie has a happy ending because Lombard’s character is a lovable fraud, a country girl putting one over on urban sophisticates. I can’t help hoping that life’s screenwriter pens a similar ending for Childs.

In an early and great episode of “The Simpsons,” Homer is convinced that he has only hours to live after eating a tainted piece of Japanese seafood. After completing an elaborate pre-death checklist, he learns that he’s been reprieved and immediately vows to never waste another moment. In the very next scene he’s shown gobbling snacks and passively watching bowling on television. The brutal truth captured in that “Simpsons” and ignored by “Live for the Moment” is that it’s impossible to seize the moment and watch television idly at the same time.

Tonight’s other highlights

• A Civil War cemetery becomes a crime scene on “Bones” (7 p.m., Fox).

• The Winter X Games (7 p.m., ESPN) opens in Aspen, Colo.

• A Grammy winner explains the origins of some of his hits on “Storytellers: John Mayer” (7 p.m., VH1).

• The 2008 documentary “Man on Wire” (7 p.m., Sundance) recalls daredevil Philippe Petit’s 1974 high-wire walk between the twin towers of the recently opened World Trade Center.

• The Bishop family tree has a few rotten branches on “Fringe” (8 p.m., Fox).

• Paired up on “Project Runway” (9 p.m., Lifetime).

• The “BBQ Pitmasters” (9 p.m., TLC) visits Vienna, Ga.