Vince Gill hosts the 37th annual Country Music Assn. Awards (7 p.m., CBS). While the winners are yet to be announced, the emotional highlight of the evening is hardly in doubt: A stage full of singers will perform a special song in honor of Johnny Cash. The Man in Black, who died at age 71 on Sept. 12, is nominated for four CMA awards. Singers Sheryl Crow, Kris Kristofferson, Willie Nelson, Travis Tritt and Hank Williams Jr. lead the tribute to Cash.

Other highlights include Alan Jackson and Jimmy Buffett performing their song “It’s Five O’Clock Somewhere,” which is nominated for Vocal Event of the Year. Dolly Parton and Norah Jones team up to sing “The Grass is Blue,” a Parton song recorded by Jones for the upcoming tribute album “Just Because I’m a Woman: The Songs of Dolly Parton.” Brooks & Dunn, Kenny Chesney and Patty Loveless are among the other scheduled performers.

• Sci-fi series are hardly immune to sweeps month gimmicks. The Superman knock-off “Smallville” (7 p.m., WB) offers a glimpse back to the year 1961. Just because that sounds like the plot to “American Dreams” don’t go looking for American Bandstand. Clark learns that a close relative, who looks one heckuva lot like our super-teen, visited Earth some 40 years back. And his mission was not exactly peaceful.
• Meanwhile, on “Enterprise” (7 p.m., UPN), Archer suffers from that most common of all primetime afflictions: amnesia! The crew tries to work around the captain’s memory loss, but to no avail. Sooner than you can say “Memento,” the curvy T’Pol and trusty Trip take command of the ship. When it comes to “Enterprise,” a lot of “Star Trek” fans seem to suffering from their own form of amnesia — they keep forgetting to watch the show.
• “Angel” (8 p.m., WB) travels south of the border to sample some cultural stereotypes. While in Mexico to observe the Day of the Dead, Angel runs into a representative from Wolfram & Hart who puts on some wrestling moves that are so old-school they go all the way back to Aztec times. Don’t eat your heart out.
• Bartlet reaches out to tornado victims on “The West Wing” (8 p.m., NBC). Meanwhile, Josh spends some time in the political doghouse for a mistake that caused a loyal congressman to jump parties. After the high drama of Zoey’s kidnapping and the invocation of the 25th Amendment, will viewers keep coming back for day-to-day Washington politics?

Tonight’s other highlights

• Carol mulls an opportunity to write and live in New York on “Ed” (7 p.m., NBC).
• A media mogul’s public triumphs and private affairs unfold in flashbacks in the 1941 drama “Citizen Kane” (7 p.m., Turner Classic Movies), written, directed and starring Orson Welles.
• Summer seethes about Seth on “The O.C.” (8 p.m., Fox).
• An identity thief’s career comes to an abrupt end on “Law & Order” (9 p.m., NBC).
• Karen’s fling with a Marlins pitcher strikes out on “Karen Sisco” (9 p.m., ABC).
• Bill Kurtis is host of “Hunting the Washington Sniper” (9 p.m., A&E).

Late night

Will Ferrell and Lyle Lovett appear on “Late Show with David Letterman” (10:35 p.m., CBS) … Jay Leno greets Matt LeBlanc on “The Tonight Show” (10:35 p.m., NBC).