10. The time a dog interrupted our interview. Dave took a break from talking to us in a 1997 sitdown to let a dog lick the makeup off of his face.
9. Howard Stern in drag. The radio shock jock got glammed up for Dave while promoting his book, Miss America, in 2009.
8. Johnny Carson's surprise drop-in. The King of Late Night and former host of The Tonight Show literally delivered the Top Ten List for Dave to present with almost no notice. "Dave only knew very late that Johnny was going to show up," The Late Shift author Bill Carter said. "Johnny just showed up and brought the Top Ten List. It was sort of like this cool moment."
7. Joaquin Phoenix. This was hands down Dave's weirdest interview. Joaquin was famously laconic and loopy throughout the exchange and later admitted that it was a ruse for his documentary I'm Still Here.
6. Rebel Wilson rendering Dave speechless. When Dave asked the actress how he knew her, Rebel responded, "Do you watch a lot of...," being cut off after giving a suggestive glance. "I was just joking," Rebel said.
5. Josh Groban singing his heart out. "He asked me to do a Top Ten List of the Top 10 rejected Josh Groban songs, and had me sing every one of them," Josh told ET.
4. Michael Strahan gives Dave a taste of the NFL. The Super Bowl champ scooped Dave right off his feet as a guest on Late Show. "It was great to be able to tackle David Letterman," Strahan told ET. "Nobody gets a chance to do that."
3. Madonna's potty mouth. The pop diva had a few choice words for Dave during a 1994 Late Show appearance. "You are always f---ing with me on this show," she told him. "She was upset because we kept making these jokes about her," Dave explained to ET. "She just went nuts."
2. Drew Barrymore's desk dance. The actress famously flashed Dave while dancing on top of his desk in 1995. "It was silly, because who among us haven't seen naked women?" Dave told ET.
1. The night he made an ET crew stars on Late Show. During a 1996 show taping, Dave brought in our cameramen from off the street, being greeted to applause from the audience inside the Ed Sullivan Theater.