‘Jag’ reflects 9/11 tragedy

Viewers have a clear choice tonight between nostalgic escapism and grim reality: a series of comic retrospectives compete with a fictional drama and a documentary dealing with the events of Sept. 11.

While “JAG” (7 p.m., CBS) often grabs plots from past headlines, tonight’s episodes anticipates events with a story involving the military tribunal of a fictional al-Qaida terrorist accused of training the pilots responsible for the attack on the World Trade Center. Harm and Mac lead the prosecution team while Admiral Chegwidden and Commander Turner volunteer provide a defense for the accused (Marc Casabani), whose arrogance and non-cooperation make his case difficult. Lacking definitive evidence, Mac travels to Afghanistan to find a credible witness, only to find his life in danger during a prison uprising sparked by Taliban and al-Qaida detainees.

Over the last seven months, the producers of “NOVA” (7 p.m., PBS) have cooperated with the American Society of Civil Engineers (ASCE) as they have investigated the collapse of the World Trade Center buildings. The documentary “Why the Towers Fell” combines eyewitness testimony, computer graphics and interviews with engineers, architects and fire-safety experts to determine why the buildings collapsed as quickly as they did, and what could have been done to avert the massive loss of life. Seven months in the making, the ASCE report will be released today, with details why the two towers fell for very different reasons. Fascinating.

Kelsey Grammer is host to “Bob Hope’s Funniest Out-takes” (7 p.m., NBC), the first of many retrospectives to coincide with May sweeps and the 75th anniversary of the NBC network. Featuring clips with Dean Martin, Phyllis Diller, Tom Selleck and too many other stars to mention, this blooper reel has been culled from four decades of Bob Hope specials, Christmas shows and his signature overseas USO tours.

An hour later, Grammer engages in a nostalgic trip of his own on “Frasier” (8 p.m., NBC), as Dr. Crane pays a visit to his old Boston bar, where everybody (Rhea Perlman, John Ratzenberger and George Wendt) knew his name. If Frasier can’t find his old bartender Sam Malone, it’s probably because “Cheers” star Ted Danson is too busy appearing on the conclusion of the 2002 made-for-television chiller “Living with the Dead” (8 p.m., CBS).

Jay Leno clearly doesn’t get as much press as his cranky late night rival maybe it’s because he’s too busy working. Over the past decade, Leno has taped 2,257 episodes of “The Tonight Show,” hosted more than 7,000 celebrity guests, and regaled his audience with approximately 47,000 monologue jokes. Why does it seem that at least 25,000 of them were about Monica Lewinsky or Judge Ito?

Leno makes a rare trip to primetime with “The Tonight Show with Jay Leno 10th Anniversary” special (9 p.m., NBC). Guests include Tom Cruise, Steven Tyler and a musical performance by Cher.

The Fox network will commemorate the 100th episode of “That ’70s Show” by turning over its entire primetime schedule to the retro comedy. In the first episode, Roger Daltrey guests stars as an overbearing music teacher and the gang rocks out to tunes by Nazareth, Peaches and Herb, the Carpenters and Steve Miller (7 p.m.). This is followed by an-hour long collection of out-takes and bloopers (7:30 p.m.) and a repeat episode (8:30 p.m.) chosen by viewers.

Tonight’s other highlights

The kids ponder parenthood on the hour-long season finale of “Dharma and Greg” (7 p.m., ABC). I hear the fat lady singing for this 5-year-old series.

Jess’ reckless behavior puts Rory’s life in danger on “Gilmore Girls” (7 p.m.).

Clark puts on his boxing gloves on “NYPD Blue” (9 p.m., ABC).

After the Strike Team is suspended, Vic (Michael Chiklis) blackmails Julien (Michael Jace) to force him to change his testimony on “The Shield” (9 p.m.).