Thanks to Tina at LittleStuff.me for this stand-up, tri-fold calendar. I printed this to use at work and it's really sweet. Be aware that they're pretty small, maybe three or four inches on each side but it's perfect for a desk or counter. I highly recommend card stock so it doesn't just blow away anytime someone opens a door.
If you want something bigger that you can write on then check out this one from Craftaholics Anonymous. The fonts are nice and the layout looks clean.