Illustrator and NYC knitter Nancy Stahl was asked by the U.S. Postal Service to create a series of non-religious holiday stamps for 2007.  She asked if she could knit the images instead of drawing them, and the USPS said yes.

Here are Nancy's stamp designs. I assume "Holiday 2007" means Oct-Dec 2007... but who the hell knows:

More info about 2007 Commemorative Stamps at USPS.com.