In normal operation, your default "channel" -- Chumby's terminology for a particular set of selected widgets -- cycles on an endless loop, and if you'd like to add widgets or channels, you log into Chumby's site to do so (though you can delete widgets and freeze the display right from the device itself if you need to).
This said, they truly work on their own, too, with each one housing an inbuilt loop sequencer for phrase-based performance, and can be sync'd to one another.