TONIGHT'S MUST-SEES

"America's Got Talent" return, 7 p.m., NBC. Here's a fresh twist — a summer show that's being stretched into October. Before the Olympics, the judges had trimmed the field to 40. Ten perform today and viewers vote. That continues Wednesday and next week.

"World's Funniest Commercials," 8 p.m., TBS. These specials are quick, slick and fun. They show commercials — European ones, in particular — that are witty, ambitious, sometimes historical. One revisits Moses; another cleverly reshapes the story of Joan of Arc.

OF NOTE

Democratic convention, noon, CNN; 5:30 p.m. PBS; ABC, CBS and 4 p.m. NBC. NBC had talked of skipping Tuesdays at both conventions, then changed its mind.

"Gavin & Stacey" debut, 2:40 p.m., BBC America (Oceanic Digital Channel 341). The British accents are tough to follow here, but Mathew Horne and Joanna Page are immensely charming as a couple finally meeting in person. James Corden and Ruth Jones, who wrote the show, get broader laughs as their crude friends.

"House," 7 and 8 p.m., Fox. Both reruns have House sparring with Wilson's love, Amy. In the first, they argue about time with Wilson; in the second, the couple has its first fight.

"The Janice Dickinson Modeling Agency" season-opener, 7 p.m., Oxygen. Overwrought and self-obsessed, Janice Dickinson is an odd centerpiece for a reality show. It's one thing to have charming quirks, another to repulse. This hour has Dickinson adding some models, buying a house and getting a top designer (Christopher Ciccone, Madonna's brother) to fix it up. By the end of the hour, she has treated her previous models with boorish disdain.

"Greek" season-opener, 9 p.m., ABC Family, rerunning at 10 p.m. Spring break is over and Rebecca stirs controversy. That puts pressure on Casey, played by Spencer Grammer (Kelsey's daughter). Meanwhile, Greek Week games threaten to split friends. This is an overcrowded episode, with some good moments near the end.