Nexus devices are truly open devices, and developers make use of them fully. In the same series, a developers a ported Meego on Nexus S. While most of the features do not work, it is still a work in progress.
• ADB root shell
• X11 & UI apps
What doesn’t work currently:
• Super-AMOLED brightness control (screen looks near pitch black)
• Anything else 😛
Find more on the porting at XDA Thread.