Jay Leno

Why doesn't anyone seem too worked up about Jay Leno leaving The Tonight Show? Maybe because he's only kind of leaving. Come fall, fans will still get to see him five nights a week, 90 minutes earlier. As we look ahead to the start of a new Tonight Show era Monday, with Conan O'Brien behind the desk, let's also look back on the most memorable moments of Leno's 17 years with the show.

5. Angie Harmon's Engagement: One way to make sure you capture your marriage proposal on camera is to do it on The Tonight Show. That was Jason Sehorn's approach when he strode onto the show's stage in March 2000 to propose to Angie Harmon. She said yes — and the video came out great.

4. Shaking John F. Kennedy Jr.'s Hand: Leno says Kennedy's May 1998 appearance was "probably the most emotional moment for me." The host remembered watching Kennedy salute his father's flag-draped coffin after his assassination, and his own mother's tears at the time. "He came around the corner and I shook his hand and I looked up in the camera and I looked up in the monitor and I saw me shaking hands with John F. Kennedy," Leno said. "And I immediately flashed to my mother, just being hysterical."

3. President Obama's Appearance: Soon after taking office, Barack Obama became the first sitting president to sit beside a late-night talk show host. He tried to reassure Americans about the economy, and made a bad joke about the Special Olympics. Whoops.

2. Arnold Schwarzenegger's Announcement: When detractors tried to dismiss Arnold Schwarzenegger as a Hollywood heavy unprepared for the California governor's office, he seized on his celebrity to announce his candidacy on The Tonight Show in August 2003. The theatrical gesture kicked off a successful campaign, giving the ex-Terminator an office he still holds. He returned to the show this week to graciously thank Leno. No, just kidding. He made fun of him for looking old. You can watch the episode here.

1. Hugh Grant's Explanation: Grant was supposed to appear on The Tonight Show in July 2005 to promote his romantic comedy Nine Months. Then he was arrested for lewd conduct in an encounter with a prostitute. Remarkably, Grant not only kept the appointment but blamed himself. "What the hell were you thinking?" Leno asked. Responded Grant: "I think you know in life what's a good thing to do and what's a bad thing, and I did a bad thing. And there you have it."

Are you excited about Leno's next show, and O'Brien taking over The Tonight Show