It takes up little space on the home screen (only one widget cell) of Android and gives a clear indication of whether builds on Hudson are stable, unstable or they are failing.
If all the builds are stable the Hudson widget is highlighted with green and Mr. Hudson is happy.
If any of the builds has become unstable the widget is highlighted with yellow and Mr. Hudson doesn't look as enthusiastic.
If there are any failing builds on the monitored page the widget gets highlighted with red and Mr. Hudson looks very upset.
And in case the build status could not be read (e.g. the server is down, authentication failed or no build information was found at the provided address) Mr. Hudson is hidden behind big question mark:
It is also possible to test the build status from the settings screen to verify whether the build status is readable in which case the state of the build will be provided next to the 'Test URL' button, otherwise 'unknown' status will be displayed (default).
At the moment widget supports monitoring only builds aggregated on the main page (either on the default 'All' view or a custom view), although, it is possible to monitor individual builds by putting them in a custom view.
To install Hudson Mood widget search for 'Hudson Mood' in the Android Market on your Android.
Update: eventual updates will be published on the Hudson Wiki !