Collocations for calendar - noun

busy, full
The group has a busy social calendar.

sporting (BrE), sports
golfing, racing, etc.
academic
social
Christian, Jewish, etc.
Gregorian, lunar, etc.

check, consult

in a/the calendar, on a/the calendar
the most important event in the year's golfing calendar

mark sth on the calendar, put sth on the calendar (both esp. AmE)
Mark the renewal date on the calendar so you don't forget.