There's an Easter egg on the single-disc widescreen edition of X-Men: The Last Stand that shows the X-Jet landing in the District of Columbia. Here I'll detail one way of navigating to the egg, but there are others.
At the first menu, highlight "JOIN THE BROTHERHOOD" and press the Enter button (or equivalent) on your DVD remote. At the next menu, highlight "FEATURES" and press Enter. At the next menu, highlight "DELETED SCENES" and press Enter. At this point, I should perhaps alert you that you are about to be asked to follow the same basic instructions for three screens in a row. At the next menu, highlight "MORE" and press Enter. At the next menu, again highlight "MORE" and press Enter. At the next menu, yet again highlight "MORE" and press Enter. When the next menu comes up, "HANK WARNS TRASH OF MAGNETO'S PLAN" will be highlighted. Press the left arrow key on your DVD remote and an X inside a circle at the upper left of the screen will be highlighted. Press Enter and text will appear on the screen that reads, "The following is a visual effects clip created in mid 2005 for an early theatrical marketing campaign. At that time, the climax of the film took place in Washington, D.C." Highlight "PLAY" and press Enter to view the clip.