Here's how to find it:
1. From the main menu on Disc 1 select "Special Features."
2. Now highlight "Main Menu" at the bottom of the screen--but DON'T press the "Enter" button.
3. Tap the Left arrow button on the DVD remote and a circular icon will appear.
4. Press Enter (or Select on some DVD remotes) and enjoy a humorous interview extra with Marvel's Stan Lee and Iron Man actor Robert Downey Jr.
If you own the Blu-ray version, from the main menu scroll down to BD-LIVE and press the Right arrow on the Blu-ray remote. A schematic of Iron Man's hand will appear. Now press Enter to see the clip.
For those who don't have the Iron Man DVD yet, and want to see the hidden clip, check it out HERE.