Marathons and commemorations are the order of the day as we enter Labor Day weekend. Animal Planet kicks off a weeklong salute to popular host and wildlife conservationist Steve Irwin, who died Sept. 4, 2006.

Over the course of the week, Animal Planet will repeat Irwin’s most popular documentaries, culminating with the unseen project “Secrets of the Crocodile” on Wednesday. The weekend’s offerings include “Crocodile Hunter: Collision Course” (6 p.m. today, Animal Planet), “Outback to Hollywood” (8 p.m. today) and “Search for the Super Croc” (7 p.m. Sunday).

¢ The Diana tributes continue. The WE network dedicates this afternoon to the late princess, featuring “You Had to Be There: The Royal Wedding” (11 a.m. today, WE), “Diana’s Dresses” (noon) and “Diana: Her True Story” (1 p.m.).

Starz will air the 2006 drama “The Queen” (8 p.m. today), starring Helen Mirren in her Academy Award-winning performance as Queen Elizabeth II coming to grips with the outpouring of grief for Diana, her estranged former daughter-in-law.

The British documentary “Diana: The Witnesses in the Tunnel” (9:45 p.m., Starz Cinema) follows, featuring interviews with photographers and others present at the fatal crash.

¢ What better way to bid goodbye to summer than by catching up with the season’s best new series? In my humble opinion, AMC’s “Mad Men” is not only the summer’s best cable show, but arguably the most rewarding and addictive series to emerge in the post-“Sopranos” era.

And there’s been a lot of competition since Tony went from onion rings to the blackout heard ’round the world. “The Bronx Is Burning,” “Damages” and “Californication” have all tried to fill the void and have found fans.

It’s interesting to note that the most emphatic post-“Sopranos” failure was “John From Cincinnati,” the very show that HBO put in “The Sopranos” coveted time slot. Apparently viewers, already scratching their heads over Tony’s fate, didn’t want to plumb the weird depths of obscure surfer mysticism.

AMC will repeat the seven previously aired episodes of “Mad Men” (9 a.m. to 4 p.m. Sunday, AMC).

For the uninitiated, “Men” is set in an advertising agency in 1960, a time when men in white shirts and ties thought they ruled the roost and working women knew their subservient place, or at least pretended to.

Creative director Don Draper (Jon Hamm) is the dark, handsome, brooding keeper of secrets – most of them about his own origins. Among the show’s many successes is its ability to string us along. It seems the more we see of Don, the less we know about him. And the more we want to find out.

So go to the beach on Sunday, play volleyball or picnic or go shopping for back-to-school supplies. But don’t forget to set your VCRs, DVRs, TiVos or whatever you use to capture this minimarathon of the best new show on TV.

Tonight’s highlights

• U.S. Open Tennis coverage (6 p.m., USA).
• On the road in search of pie on “Feasting on Asphalt” (7 p.m., Food).
• Amber Tamblyn (“Joan of Arcadia”) stars in the cable drama “Normal Adolescent Behavior” (8 p.m., Lifetime).

Sunday’s highlights

• U.S. Open Tennis coverage (6 p.m., USA).
• Pierce Brosnan, Gerard Butler and Maria Bello star in the 2007 thriller “Shattered” (8 p.m., TNT).
• One bongo player too many on the season finale of “Flight of the Conchords” (9:30 p.m., HBO).