Imagine a time when an orchestra conductor and serious symphonic composer could create a pop-culture phenomenon bigger than “High School Musical.”

Blending “serious” composition with jazz, swing and Latin sounds, this musical was not a call to bubble-gum escapism but a story of urban gang violence adapted from a Shakespearean tragedy.

It really happened. That composer was Leonard Bernstein, and that creation was “West Side Story,” a musical that generated a best-selling soundtrack album and a hit movie nominated for 10 Oscars.

Conductor/composer Michael Tilson Thomas hosts a “Great Performances” (8 p.m., PBS, check local listings) presentation of “Carnegie Hall Opening Night: A Celebration of Leonard Bernstein.” Thomas leads the San Francisco orchestra in extended performances of the 1944 “Fancy Free,” “West Side Story” and Bernstein’s final opera, “A Quiet Place” from 1983. He also offers commentary about Bernstein’s personality and how his music was often autobiographical.

l Was Illinois invaded by alien spacecraft in 2004? If that question sounds preposterous, you’re probably not a fan of “UFO Hunters” (9 p.m., History), now entering its second season.

While I’m not the kind of guy to encourage drinking games, “Hunters” watchers could get pretty inebriated if they took a gulp every time an expert launched into a speculative conditional statement, such as “this ‘could have been’ an alien spacecraft.”

Experts here look at video of something and suggest that it “could have been” as large as 1,500 feet across. And later, it’s suggested that it “could have been” larger than any aircraft ever sighted. Or, as others contend, it “could have been” a hoax.

¢ The new series “Shaken Not Stirred” (8 p.m., MyNetwork) offers Vegas-style roasts of public figures featuring tough love from a gallery including Anthony Anderson, D.L. Hughley, Paul Rodriguez and John Salley. The first guest to feel the fire is the Rev. Al Sharpton. Upcoming participants include Pamela Anderson, Bobby Brown, Rev. Run and Ice-T.

¢ Known for colorful films with a whimsical bent, Rick Sebak (“A Hot Dog Program”) takes “A Ride Along the Lincoln Highway” (7 p.m., PBS, check local listings), a road connecting New York and San Francisco via 14 states that was conceived in 1913. The film explores how the arrival of the car and highway culture changed the food, family and traditions of each state.

On a similar note, “Six for the Road” (9 p.m., TLC) follows a family of six as they cross America in an RV. “Six” concludes next week.

¢ Two generations of epidemic rates of teenage pregnancies in the United Kingdom have created a novel social phenomenon: the 30-something grandmother. The documentary “Britain’s Youngest Grannies” (8 p.m., BBC America) looks at women who aren’t quite ready for the rocking chair.

Tonight’s other highlights

¢ The campaign of Sen. Barack Obama presents a Paid Political Program (7 p.m., CBS, Fox, NBC).

¢ Murder is on the menu at a Chinese restaurant on “Pushing Daisies” (7 p.m., ABC).

¢ World Series Game 5 (7:30 p.m., Fox) continues in the sixth inning after Monday’s rainout.

¢ A young archaeologist pays for his discovery on “CSI: NY” (9 p.m., CBS).