No comedy does a better job of balancing the need for imparting “lessons” with its inspired anarchy than “My Name is Earl” (7 p.m., NBC). During Earl’s karmic quest for atonement he recalls an act of grade-school cruelty. When a new girl was introduced to his seventh-grade glass, he took one look at her facial hair and loudly dubbed her “Maggie PI,” after the Tom Selleck drama of the time. The name stuck and she was shamed into home schooling.

Decades later, Earl tracks down his hirsute former classmate only to discover that Maggie (Judy Greer) has become a full-fledged bearded lady, living among other carnival attractions in a posh condo compound called Shady Grove. The fact that social outcasts live in relative middle class splendor while Earl, Randy, Joy and the Crab Man subsist in cheap motels and squalid trailers is one of this show’s many unspoken ironies.

Earl learns tolerance and recalls painful memories from his past while partying with Maggie, the Fat Lady, Lobster Boy and other new friends. Meanwhile, Joy has her own prejudices put to the test when she cracks wise about her hearing-impaired defense attorney.

¢ Speaking of notable guest stars, John Mahoney (“Frasier”) appears on “ER” (9 p.m., NBC) as an ailing patient’s partner who quarrels with his family over life-saving treatment.

¢ On a night crowded with hospital melodramas, PBS launches the four-part series “Remaking American Medicine: Health Care for the 21st Century” (9 p.m., PBS, check local listings). Tonight’s installment discusses the scandalous fact that medical care itself has become one of America’s biggest killers. Every year, more than 98,000 patients die as a result of medical errors.

Tonight’s other highlights

¢ The Mets host the Dodgers in game 2 of the National League Playoffs (7 p.m., Fox).

¢ Irked by Michael’s contempt for hard work, Angela pressures Dwight to challenge his authority on “The Office” (7:30 p.m., NBC).

¢ Four cases unfold from the perspectives of the deceased on “CSI” (8 p.m., CBS).

¢ Preston’s tremors require attention on “Grey’s Anatomy” (8 p.m., ABC).

¢ A video from out of the blue causes Laura to doubt her late husband’s fidelity on “Six Degrees” (9 p.m., ABC).

¢ An armed and disturbed man sparks a raid on “Detroit SWAT” (9 p.m., A&E).