If there's one thing that the desktop world has that Android desperately needs, it's multiple user support. A shared Windows machine or a Mac both support multiple user profiles on a single device. While this isn't that big of a deal on phones, tablet users might find it unsettling passing around a shared device tied directly to their all-knowing Google account. Enter SwitchMe, an app to help alleviate the uncertainty. This root app allows users to boot into multiple profiles within a single ROM.
The app creates a sandbox for individual profiles, including applications, settings, and data that are stored on the device and loaded when logging in. A user could use this functionality to create public profiles for family use, to isolate a power user profile so others aren't slowed down by a ton of background processes, or simply as a sandbox for testing apps.
If you're interested in playing around with the app, we'd recommend first hitting up the XDA thread here for the requisite warnings and instructions before hitting the widget below to grab it from the Market.The free version allows for two profiles with no password protection, so you'll have to shell out a couple bucks if you want the whole shebang.