Fr Tim Finigan has started his posts on The Hermeneutic of Continuity this year with an extremely useful guide as to how to obtain Plenary Indulgences, both on a day by day basis and on particular days. For those he provides a list of both fixed days and variable anniversaries. It can be read at Plenary indulgences for particular days.
I missed out on January 1st, but his list gives a quick guide for planning ahead, as well as providing for obtaining a Plenary Indulgence as part of one's regular spiritual discipline. It is the sort of information that would not come amiss in the porch of every church.