As most television fans know, May sweeps is the period when networks try to maximize ratings, so they can charge hefty rates for their advertisers. Sweeps is also the time when almost every series goes on a stunt-casting binge. Tonight’s schedule is jam-packed with cameos, walk-ons and special appearances.

Sherilyn Fenn (“Twin Peaks”) continues her role as Pacey’s older woman on “Dawson’s Creek” (7 p.m., WB). “Freaks and Geeks” alum Busy Phillips also continues her recurring role as Audrey.

“My Wife and Kids” (7 p.m., ABC) recruits talent from basic cable. Kym E. Whitley (from BET’s “Oh Drama!”) appears as Michael’s former girlfriend. Her shapely appearance and dynamic professional life inspire Janet to undertake a complete makeover.

Twenty years after the death of John Belushi (and two days after ABC aired the morbid biopic “Gilda Radner: It’s Always Something”) “According to Jim” (7:30 p.m., ABC) features a Belushi-Aykroyd reunion. Dan Aykroyd guest stars as an old buddy and band mate who inspires Jim to reprise his partying lifestyle.

Mark Harmon, star of “Chicago Hope” and “St. Elsewhere” will appear on “The West Wing” (8 p.m., NBC) as a secret service agent assigned to CJ (Allison Janney). Harmon’s character will appear on the White House drama for the next four episodes, concluding with the May 22 season finale. Meanwhile, Bartlet’s staff bristles when they get the news of Russian military assistance to Iran that might jeopardize an important summit meeting.

Billy Crystal appears as himself on a very funny episode of “The Bernie Mac Show” (8 p.m., Fox). Bernie asks Jordan to fake an asthma attack so they pretend to go to the hospital and sneak off to an NBA game. Next is a repeat episode (8:30 p.m.) where Bernie plays host to fellow corporate spouses. An episode of “Greg the Bunny” (which was to have featured a cameo by Gary Oldman!) has preempted. Not a good sign for this furry, funny comedy.

Television viewers of a certain age know June Lockhart either as Lassie’s mother or Maureen Robinson from “Lost in Space.” Lockhart returns to the “The Drew Carey Show” (8 p.m., ABC) as Lewis’ mother, who reveals the reason why he can’t keep a job, or girlfriend, or speak a complete sentence. He’s really a genius. A repeat follows (8:30 p.m.) in which Drew quits the department store and makes ends meet by taking in two gay boarders (“Batman” star Adam West as well as Max Gail).

Tonight’s other highlights

Scheduled on “60 Minutes II” (7 p.m., CBS): a secret mission to capture a terrorist.

A cyber-maniac threatens to expose the Wolf Lake pack on his Web site on the series finale of “Wolf Lake” (8 p.m., UPN).

“Frontier House” (8 p.m., PBS) concludes.

“48 Hours” (9 p.m., CBS) examines the suggestive imagery and blatant sexual content in the songs and videos aimed at the teen audience. It features an interview with Justin Timberlake of N’SYNC.

A lie about a young baseball player’s age may have inspired a homicide on “Law & Order” (9 p.m., NBC).

Diane Sawyer is host to a “Primetime Special Edition” (9 p.m., ABC) examining the case of a Knoxville, Tenn., man accused of killing four women. He argues that the confession was not his own but that of one of his multiple personalities.

Cult choice

Marlon Brando, Vivien Leigh, Karl Malden and Kim Hunter star in the 1951 Tennessee Williams drama “A Streetcar Named Desire” (7 p.m., Turner Classic Movies).

Series notes

Principal Dennis scuttles Carol’s plans for the quiz team on “Ed” (7 p.m., NBC) … Hal tries to pry jury duty secrets out of Lois on “Malcolm in the Middle” (8 p.m., Fox)