Here are some fun iPad features that a friend showed me last night. As per some of my previous iOS 5 tips, they're tucked away in Settings > General > Accessibility. Below is the main Accessibility pane with Zoom and Triple-click Home annotated:
Zoom - Double-tap three fingers. Touch the Zoom setting in Accessibility to turn this one on (it's off by default) and you can easily zoom in on an area on the iPad by double-tapping three fingers. This feature seems to have trickled down from Mac OS X's System Preferences > Universal Access > Zoom and is great for giving demos to someone across the table or room.
The zoom itself is only one level deep (roughly 175%) and isn't customizable. It zooms directly in on the area that you double-tapped and is reminiscent of double tapping to zoom in Mobile Safari on the iPhone. The zoom itself can't be captured in a screenshot, but above are its settings.
Triple-clicking the Home button. Another fun setting hidden in Accessibility is the ability to map triple-clicking the Home button to one of four macros. In the screenshot above I have mine set to Toggle White on Black, a featured designed to help the visually impaired. I sometimes find black-on-white mode (pictured below) to be easier on my eyes for reading - especially at night.
Like the Zoom setting above, the black on white mode also trickled down from Mac OS X's System Preferences > Universal Access > Display.
Since black-on-white mode isn't screenshot-able, I've simulated it using Photoshop's Image > Adjustments > Invert. Below is my normal iPad desktop, followed by it in black-on-white mode.