I love Chinaberry.com. When our house sale in Wyoming closed, I ordered the perpetual advent calendar pictured below. The box sizes are varied, so you could put actual small treasures in them, but we've been doing it like a treasure hunt. Each night after Bret gets home I put a note in the appropriate date and give the girls clues to where they can find that day's prize (an edible treat/holiday book/tickets to see a holiday show/a $1 bill for each girl/etc...). It's been a really fun way to count down to Christmas, and to get to know some of the nooks and crannies of our new home.
Of course, we've also enjoyed the chocolate-a-day calendars that Uncle Brian and Aunt Livia sent...Vivian ate all her chocolates on day 2...not Sabine, she takes this stuff seriously.