I built a clock with iCal support with the LILY Pi. Everything seemed to work, although I found it challenging to reproduce the example application, but once I did, things were fine. Eventually, I rearranged to build in Visual Studio with platform.io which I like a lot more; I feel there's more clarity than the Arduino IDE.

Currently I have one device at home, and a second in the field, which a friend is planning to use once I make some timezone adjustments (Google stopped providing vtimezone data for new calendars, apparently, so I need to get it somewhere else).