I'm using a Raspberry Pi (Gen 1, Model B I think) to run a smart mirror. It pulls up my daily commute, news headlines, weather, and calendar. I take no credit for the software (
https://github.com/MichMich/MagicMirror)
I also had one connected to my Motorola LapDock back in 2012 to run a portable raspbian laptop. It worked surprisingly well.