The Plant Conservation Alliance's Alien Plant Working Group has put out their 2007 "Weeds Gone Wild" calendar as a pdf you can download and print out. And...surprise!...my photos are featured in March, April and August. Gotta love Creative Commons licensing :-).
Or, if you are feeling too lazy to print out your own calendar, consider purchasing the 2007 Invasive Species Weblog Wall Calendar. It's glossy, semi-professional-looking, and spiral-bound, and all profits I make from the sale of the calendars (as for any products from the ISW store) go to charitable invasive-species causes.