Homemade Advent Calendars

My kids love and look forward to their advent calendars every year. I want to do something a little different this year and am toying with the idea of making my own. I love the idea of filling little boxes with inexpensive little goodies - chocolate coins, chapstick tubes, silly little nothings really, but I also like the idea of creating an advent calender with fun Christmas related things to do - go on a Christmas lights drive, put on Christmas carols, write letters to Santa, bake cookies... things of that nature, or maybe even create a little scavenger hunt. As usual I am looking for ideas that are simple and easy to create.