A calendar for 2018 has been prepared by Peter Wilson of Herries Press for anyone who's interested: a4, letter. Thanks Peter!
Each TUGboat issue contains a calendar of TeX and typography events, among other news and announcements. If you have an event you would like to have included, please send information to firstname.lastname@example.org.
A list of TUG meetings, and some other TeX events, is also available.