These are my go to places every month for
fantastic desktop calendar-wallpapers:

1. Simple Blueprint

2. Lisa Rupp on Flickr

3. Design*Sponge

Plus 2 amazing wallpaper collections :

A Beautiful Ripple Effect’s collection & of course,
The Desktop Wallpaper Project!

Do you have any to add to the list? Comment please!
I’d love to check them out!