Television has the power to bring us the world. But, too often, all we get is Regis Philbin. Given the medium’s potential for showing us the full range of human expression and experience, the results are pretty sad. But on rare occasions television lives up to its promise, and “Going Tribal” (9 p.m., Discovery) is a good example of that happy moment.

Now in its second season, “Tribal” follows former Royal Marine Bruce Parry as he travels through Africa exploring some of the quickly disappearing tribal cultures, their ancient, adventurous traditions and dangerous rituals.

In tonight’s episode, Barry returns to the Omo Valley in Ethiopia. After revisiting the Suri people featured in last season’s “Tribal,” he crosses the Valley to spend time with the Nyangatom tribe, the Suri’s arch rivals. Life in the Omo is difficult, and the Nyangatom have developed a warrior culture with elaborate rites of sacrifice. Bruce immerses himself in their ways and dons warrior paint and costume to spear a bull and drink its clotted blood.

¢ There’s bad news for “Gilmore Girls” (7 p.m., WB). And I’m not just talking about weird vibes between Lorelai and Luke. The team of Amy Sherman-Palladino and executive producer Dan Palladino, the creative force behind “Girls” for the past six years, has quit the series after a contract dispute with the studio. There’s no certain word if “Girls” is going to be part of the new CW Network. But now, even if it does return, it may not be the same “Girls.”

¢ While director D.W. Griffith’s 1915 Reconstruction epic “The Birth of a Nation” (7 p.m., TCM) reflected the prevailing racism of its time, it also marked a revolution in moviemaking, establishing a grammar of cinematic drama that endures to this day.

¢ Danger strikes close to home on “House” (8 p.m., Fox) as Dr. Foreman contracts a mysterious brain disease from a police officer admitted to the hospital after taking a stray bullet. This story concludes tomorrow night.

¢ Cast members reminisce on “Dynasty Reunion: Catfights & Caviar” (9 p.m., CBS). “Dynasty” aired on ABC from 1981 to 1989, but it lost most of its audience after the royal wedding/Moldavian terrorist cliffhanger episode in May 1985.

Tonight’s other highlights

¢ Only five remain on “American Idol” (7 p.m., Fox).

¢ Dangerous weapons must be retrieved on “The Unit” (8 p.m., CBS).

¢ Television viewers find Pepper unlikable on “Pepper Dennis” (8 p.m., WB). Talk about art imitating life!

¢ Natalie Cole guest stars on “Law & Order: Special Victims Unit” (9 p.m., NBC).

¢ Alan’s advice lands him in the slammer on “Boston Legal” (9 p.m., ABC).

¢ “Music From the Inside Out” on “Independent Lens” (9 p.m., PBS, check local listings) follows members of the Philadelphia Orchestra inside and outside the concert hall.

¢ “Costas NOW” (9 p.m., HBO) features an interview with Willie Mays.