David Letterman celebrates his 65th birthday today. For those who can recall Letterman's early years as a goofy, youngish guy in a sport coat, that milestone may come as something of a shock. He's been a part of late-night TV for 30 years. "Late Night With David Let terman" debuted on NBC on Feb. 1, 1982, with Bill Murray as the first guest. Murray returned to mark the anniversary this past Feb. 1 on "Late Show With David Letterman," where Dave has held court on CBS since 1993.

It would be easy to focus on Letterman's age and long run. But they somewhat obscure the fact that with a couple of exceptions, nobody on late night is a kid. Jay Leno turns 62 in a couple of weeks. Jon Stewart and Craig Ferguson turn 50 this year, Conan O'Brien will do so next year and Stephen Colbert the year after.

It's interesting to note that Johnny Carson, the legendary template for all talk show hosts, took over "The Tonight Show" when he was 37. Chelsea Handler and Jimmy Fallon are 37. Jimmy Kimmel is 44. Their comparative youth may explain some of their success.

Much has been written about the wars for late-night dominance. But with a median age nearing 50, many late-night hosts are nearly a generation older than their intended audiences of 20-somethings. Could that be why Cartoon Network's "Adult Swim" regularly beats many of the late-night funny guys? It's a blunt fact of life. Older viewers don't stay up that late. And younger viewers may not always want to watch the stuff that made their

parents laugh.

On May 14, "Ameri can Masters" on PBS will air "Johnny Car-

son: King of Late Night," commemorating the 50th anniversary of his "Tonight Show" debut and the 20th anniversary of his departure.

---A lost engagement ring sets up a proposal re-enactment on the season finale of "Up All Night" (9:30 p.m., NBC, TV-14). This show has not yet been renewed for a second season.

OTHER HIGHLIGHTS

---John Goodman guest stars on "Community" (8 p.m., NBC, TV-PG).

---A contestant goes home on "American Idol" (8 p.m., Fox, TV-PG).

---Michael takes the initiative on "Missing" (8 p.m., ABC, TV-PG).

---To drum up business, Joe throws a Trucker Appreciation Weekend on "Truck Stop USA" (8 p.m., Travel).

---Liz tries to make Jack show he cares when his mother (Elaine Stritch) is hospitalized on "30 Rock" (8:30 p.m., NBC, TV-14).

---The machine churns out too many names and numbers on "Person of Interest" (10 p.m., CBS, r, TV-14).

---A reluctant party-

planning staff digs in its heels on "The Office" (9 p.m., NBC, TV-PG).

---Martin encounters a grieving woman bent on revenge on "Touch" (9 p.m., Fox, TV-PG).

---Owen comes clean under duress on "Grey's Anatomy" (9 p.m., ABC, TV-14).

---A competition attracts tourists to the San Diego Zoo on "Sand Masters" (9 p.m., Travel).

---Laura Innes ("ER") guest-stars on "Awake" (10 p.m., NBC, TV-14).

---A client's Rolodex threatens to rock the nation's capital on "Scandal" (10 p.m., ABC, TV-14).

---"Independent Lens" (10 p.m., PBS) presents "When the Drum Is Beat ing," a look at Haiti's rich musical tradition.

CULT CHOICE

Meryl Streep, Bruce Willis and Goldie Hawn star in the 1992's "Death Becomes Her" (8:15 p.m., Cinemax).

SERIES NOTES

---Jeff feels used on "Rules of Engagement" (8:30 p.m., CBS, TV-14).

LATE NIGHT

---Esperanza Spalding is scheduled on "The Daily Show With Jon Stewart" (11 p.m., Comedy Central).

---Jim Gaffigan and Arctic Monkeys appear on "Conan" (11 p.m., TBS).

---Jeff Wild, Arden Myrin and Brad Wollack are booked on "Chelsea Lately" (11 p.m., E!).

---Ben Rattray sits down on "The Colbert Report" (11:30 p.m., Comedy Central).

---Billy Crystal and Alabama Shakes appear on "Late Show With David Letterman" (11:35 p.m., CBS).

---Jay Leno welcomes Chris Diamantopoulos and Feist on "The Tonight Show" (11:35 p.m., NBC).

---Danny McBride, Dianna Agron and the Shins appear on "Jimmy Kimmel Live" (midnight, ABC).

---Tina Fey, John Slattery and David Chang visit "Late Night With Jimmy Fallon" (12:35 a.m., NBC).

---Craig Ferguson hosts Judd Apatow and Katherine Jenkins on "The Late Late Show" (12:35 a.m., CBS).

Kevin McDonough can be reached at kevin.tvguy@-

gmail.com.