David Letterman's most memorable Late Show moments

Today marks the 25th anniversary of the debut of the Late Show With David Letterman, which ended its impressive and always hilarious run in 2015. To celebrate Letterman and his namesake show, EW has compiled a list of nine particularly memorable moments.

Madonna’s 1994 Late Show appearance was so controversial that there’s an entire Wikipedia page dedicated to it. From 14 F-bombs to endless sexual innuendos to the pair smoking cigars, let’s just say the Queen of Pop’s appearance was nothing short of memorable.

Sporting an outfit just about as outlandish as Madonna’s ’94 appearance, Gaga hilariously recounted her experience growing up in New York and fighting for her career.

It’s safe to say that audiences were left quite confused after Phoenix's 2009 Late Show visit. Many questioned Phoenix’s state of mind when, sporting an overgrown beard and sunglasses, he announced that he was abandoning his thriving acting career to try his hand at hip-hop. Alas, the actor returned to the show the next year to apologize and reveal it was all part of his controversial mockumentary I'm Still Here.

Broadway made its way to the Letterman stage in the form of a singing Green Goblin (Patrick Page) and friends in 2011. The over-the-top tune "A Freak Like Me Needs Company," from Spider-Man: Turn Off the Dark, delivered both a showstopping spectacle and an unforgettably weird TV moment.

Letterman held nothing back, asking Hilton about her time in jail within the first 20 seconds of the interview. The socialite became increasingly irritated as she attempted — unsuccessfully — to change the subject, and Letterman questioned her about everything from the food in jail to how the experience changed her.

In his first episode back after the Sept. 11 attacks, just six days later, Letterman gave a memorable speech in support of then-Mayor Rudy Giuliani, touched on the fallen first responders, and gave words to an event that felt indescribable to many at the time.

Rupert Jee, the owner of the nearby Hello Deli, made multiple appearances on Letterman's show, including one particularly memorable segment titled "Top Ten Things I've Always Wanted to Say to Hello Deli Customers." (Also, shout out to Mujibur and Sirajul!)

Leave it to Drew Barrymore to deliver arguably the most memorable moment in Late Show history. The then-20-year-old starlet surprised Letterman with a table dance for his birthday, ending with a splash… or shall we say flash?

In 2000, Letterman went under the knife for quintuple-bypass surgery, leading to a one-month break from the Late Show. In one of the most poignant moments in late-night memory, he gave a teary-eyed speech and brought out the medical team that operated on him, telling the audience that they saved his life.