The ads, placed along highways in North Carolina and Colorado, have irked some people.

"It can be insulting to those who are religious and do celebrate it for Christianity and religion in general," said Alexis Esselman.

The group said it purposefully places billboards in areas where they might raise more eyebrows and start a discussion.

"We want it to be either a little funny or edgy or provocative in some way so when people see it, they stop and go, 'Hey, wait a second. What did that just say?'" said Nick Fish, program director of American Atheists National.

Some people are firing back by donating to Signs of Christmas, an organization that puts up billboards featuring the nativity scene.

This video includes an image from Getty Images.