TONIGHT'S MUST SEE

"Hacking Democracy," 7 p.m., HBO. In 2000, a Florida county originally showed Al Gore with a total of minus 16,022 votes. That was corrected, of course, but it set writer Bev Harris on a mission to see how fallible and vulnerable vote-counting computers can be. She soon found: The complete inner workings of the software of the Diebold Corp., which counted 40 percent of the presidential votes in 2000. It was accidentally available online and experts said they could use it to tamper with the system. "One person could be responsible for changing tens of thousands of votes," said David Dill, a computer science professor at Stanford University.

"My Name is Earl," 7 p.m., NBC. Roseanne Barr guest-stars as the former head of the trailer-park association where Earl and Joy lived. Long ago, Earl changed her life by making her think she was hearing the voice of God. Now he tries to make amends.

OF NOTE

"Ugly Betty," 7 p.m., ABC. Betty's boss lusts after a new woman. Meanwhile, his rival Wilhelmina (Vanessa L. Williams) gets a surprise visit from her daughter.

"The Office," 7:30 p.m., NBC. Nancy Walls, real-life wife of star Stephen Carell, has another guest shot as his girlfriend, Carol. In support of Kelly, they head to the Diwali celebration, the Hindu festival of lights.

"Grey's Anatomy," 8 p.m., ABC. Embeth Davidtz, the Oscar-nominee from "Schindler's List," arrives as Derek's sister.

"ER," 9:01 p.m., NBC. As the malpractice verdict nears, Kovac and Curtis Ames (Goran Visnjic and Forest Whitaker) wait nervously. Meanwhile, Morris (Scott Grimes) awaits his TV debut and Neela (Parminder Nagra) pushes for better duties.