There are several Community Events Calendars. Below are the links. (As I find more, I shall post them here.)
Started by Lilikate Buggins, Rosalie Rumble, the current columnist, posts a new Community Events Calendar column each week. Though it originally mostly contained Landroval activities, it now more widely lists activities on other servers as well. Find it on lotroplayers.
http://lotroplayers.com/
Floradine Strongfoot has an Activity Calendar on the main page of her social website, LotroArtists. It covers a number of servers.
http://lotroartists.com/
Laurelin has at least 2 websites that list some of the Social Events on Laurelin. The Bramblebury Gazette lists the Shire Activities. Lina's Biscuity Burrow also has an Activity Calendar, a bit fancier than that of the Bramblebury Gazette, but both are quite serviceable. It, too, is devoted to Shire Activities.
http://www.brambleburygazette.com/
http://www.linawillow.org/home/
Gaming Gal has begun posting Landroval events on the LOTRO Forums>Server>Landroval. The thread is "Happenings on Landroval".
https://www.lotro.com/forums/showthread.php?573818-Happenings-on-Landroval