The season has not been kind to “Ally McBeal” (7 p.m., Fox). As its ratings have tumbled, the overly cute legal fantasy has all but fallen off the pop culture radar screen. The comedy really never recovered from Robert Downey Jr.’s departure last season after a drug arrest. Viewers have not warmed to the appearance of Jersey Shore heartthrob Jon Bon Jovi or Dame Edna. After a five-week hiatus (when the timeslot was filled by the lame “McBeal” imitation “American Embassy”) “Ally” returns with a memorable night of stunt-casting.

“Friends” star Matthew Perry appears on tonight’s two-hour special episode as a cranky lawyer who makes a shambles of Ally’s professional life. A guest spot by the star of TV’s favorite comedy can’t help but boost interest in “Ally.” It’s also a welcome departure for Perry, whose character Chandler has been the least interesting part of this season’s “Friends” resurgence.

With “Friends” wrapping up after one more season, Perry is smart to explore other acting opportunities. America’s video store shelves overflow with failed movies starring “Friends” actors Jennifer Aniston (“Rock Star”), Matt LeBlanc (“Ed”) and most notably David Schwimmer (“Kissing a Fool”). The best screen performance featuring one of the “Friends” quartet has to be by Lisa Kudrow in the caustic 1998 comedy “The Opposite of Sex.” That film starred Christina Ricci, who also makes a guest spot on tonight’s “Ally McBeal.”

 Combining ultra-violence, withering teen irony and a bizarre tongue-in-cheek mythology all its own, tonight’s “Angel” (8 p.m., WB) takes the over-the-top series to new heights of creative weirdness. Highlights include Angel’s trip to the “white room,” an other-worldly conference chamber at the evil law firm of Wolfram & Hart. There he encounters a smug seven-year-old female oracle who provides clues to the location of Angel’s missing son.

 Three years after the Columbine High School shootings, “Investigative Reports” (9 p.m., A&E) presents the findings of the Threat Assessment Group (TAG), a panel of forensic psychiatrists assigned to find out why Eric Harris and Dylan Klebold murdered 12 students and one teacher. After violent incidents, the TAG team perform a “psychiatric autopsy” looking for clues to what turns angry individuals into killers. They hope that their findings will help parents, teachers and authorities learn the warning signs that may prevent future tragedies.

l “Cinemax Reel Life” (6 p.m., Cinemax) dedicates every night this week to the series “Broken Silence.” Sponsored by Steven Spielberg and the Survivors of the Shoah Visual History Foundation, “Silence” presents five foreign language documentaries about the Holocaust, beginning tonight with “Eyes of the Holocaust” from Hungarian director Janos Szasz.

Tonight’s other highlights

 Anne Archer and Robert Urich star in the 2002 “Night of the Wolf” (7 p.m., Animal Planet).

 Debra’s thoughtless wisecrack endangers domestic tranquillity on “Everybody Loves Raymond” (8 p.m., CBS).