Jay Mohr is host of the new talent/reality showcase “Last Comic Standing” (8 p.m., NBC). Ten standup quipsters will share a house (a la MTV’s “Real World”) and face elimination every week (as on Fox’s “American Idol”). The final funny man or woman wins a deal with NBC and a will get a special on Comedy Central.

Mohr’s last prime-time effort was the off-color 1998 Fox comedy “Action.” The series’ showbiz setting and obscenity-laced dialogue won over some critics (not this one), but failed to find an audience. Mohr reportedly said, “I didn’t know there were six networks until I learned that ‘Action’ had come in sixth.” Now that’s funny!

• “The Osbournes” (9:30 p.m., MTV) return with the last six original episodes of their second, and final, season. Tonight: the family celebrates young Jack’s 17th birthday at a Medieval Times theme restaurant.

Tonight’s other highlights

• Pint-sized talents compete on “American Junior” (7 p.m., Fox).
• Crime stalks the racetrack on “Keen Eddie” (8 p.m., Fox).
• Moisturizer mayhem on “America’s Next Top Model” (8 p.m., UPN).
• Two victims are discovered bound, gagged and dead on “NYPD Blue” (9 p.m., ABC).
• Leaving Las Vegas on “Lucky” (9 p.m., FX).

Series notes

Vehicular homicide on “JAG” (7 p.m., CBS) … Brooke Burns is host of “Dog Eat Dog” (7 p.m., NBC) … On back-to-back episodes of “8 Simple Rules” (ABC), Paul likes Bridget’s jock boyfriend (7 p.m.), Rory steps out (7:30 p.m.) … Buffy takes a job as a guidance counselor on “Buffy the Vampire Slayer” (7 p.m., UPN) … On back-to-back episodes of “Smallville” (WB), red Kryptonite affects Clark badly (7 p.m.), a strange substance inspires odd behavior (8 p.m.).

Gang violence on “The Guardian” (8 p.m., CBS) … No receipt, no return on “According to Jim” (8 p.m., ABC) … Claude’s perks inspire envy in the office on “Less Than Perfect” (8:30 p.m., ABC) … Michael accelerates his custody battle on “Judging Amy” (9 p.m., CBS).

Late night

Bruce Willis and Damien Rice appear on “Late Show with David Letterman” (10:35 p.m., CBS) … Jay Leno greets Josh Hartnett, Kelly Clarkson, Justin Guarini and Heart on “The Tonight Show” (10:35 p.m., NBC).

Julianna Margulies, Michael Chiklis and Jewel are booked on “Late Night with Conan O’Brien” (11:35 p.m., NBC) … John Corbett and Bobby Lee are on “The Late, Late Show with Craig Kilborn” (11:37 p.m., CBS).