Jono Bacon, the Ubuntu Community Manager, has posted a video today in which he shows the current state of Ubuntu Phone OS running on a Galaxy Nexus.
In the video you can see some of the core functionality like receiving a phone call and text, multitasking, as well as some apps like the weather app, web browser, Friends (the social networking application) and more. The phone lags at times and Jono says that's because "there hasn't been any performance management that's been done yet, the team has been working on just getting the core functionality working".
You can watch the Ubuntu Phone demo video below:
(direct video link)