[ale] Calendar server suggestions

[Alex Carver]

A few things have come up that now suggest I really need a shared
calendar to sync between my phone (Android) and client applications
(Thunderbird and something on a Mac, not sure yet).

I was trying to search around and I see things like Radicale and DAViCal
but do any of you have a suggestion for something very light weight that
can handle several clients?  Doesn't necessarily need a web interface
and it won't be public (accessible only via local network or VPN).