I like to print blank calendar pages to use as a rough draft. This allows me to put down mere possibilities, rather than marking and erasing on a paper calendar or deleting with no trace on an electronic calendar. Begin summer planning with the events that have certain dates. Put any vacations, summer camp, houseguests, day trips, holidays, etc. that you know on the calendar. Also add any important work-related dates, i.e. deadlines, vacations of colleagues, business travel, etc. Now you have a rough idea how many days or weeks for which you’ll need to make a summer plan.