Pixel density hack changes your Honeycomb tablet interface to Gingerbread
After getting root access, finding and changing the pixel density to 170 or higher and rebooting afterwards would take you to the Gingerbread UI, more common on phones. Reverting back to Honeycomb is as easy as editing the pixels per inch to 160 or less and reboot the device. After all, it seems that Google might have not exactly taken a ground-up approach when building its tablet-optimized user interface, doesn’t it? Check out the video demonstration below for yourself and don’t hesitate let us know which one you prefer and why.
source: Android Community