I bought a cheap Android tablet from China recently, it was $60 including shipping. Despite the hilariously bad translation in the documentation, it works great, although slowly. The idea was to mount the tablet on the wall near the front door, and have it show some relevant real-time information. After a week of procrastinating, I finally wrote it. The source is up on GitHub. The code is very messy and needs to be re-factored and commented, but it works.
The app gets data from 3 data sources, the Yahoo! Weather RSS Feed, the WMATA developer API and the Capital Bikeshare Station XML feed. The data is updated every 30 seconds and has works remarkably well. As a metro train approaches, the background of the text turns yellow and red as the window of opportunity for catching the train closes. The status of 2 Bikeshare stations is also shown, the station closest to my house, and the station nearest my gym.
One feature that I’d like to add if I have time, is to add a rotating background that updates from Facebook automatically.