Have a mountain of leftover Keurig K-Cups? Cut the clutter by upcycling them into this no-average-Joe Advent calendar. Start by punching two-inch circles into holiday-patterned paper, then sticking adhesive numerals to the circles. Tape each circle on top of a clean K-Cup filled with candy. Hot-glue the cups to a cardboard tree cutout to finish the calendar—and start the holiday fun!