Nearly two years ago, the United Coalition of Reason offered to pay $5,700 to the Port Authority of Allegheny County (in Pennsylvania) to put up 12 king-sized bus ads over the course of a month to advertise the newly-formed Pittsburgh Coalition of Reason.
MORE: http://www.patheos.com/blogs/friendlyatheist/2013/11/28/two-years-after-rejecting-atheist-bus-ads-port-authority-of-allegheny-county-gets-sued/
See also...
Group sues Pa. transit agency over non-theist ads
http://www.washingtonpost.com/national/group-sues-pa-transit-agency-over-non-theist-ads/2013/11/27/f4d351b6-576b-11e3-bdbf-097ab2a3dc2b_story.html
Port Authority faces suit over 'Godless' ads
http://www.post-gazette.com/local/2013/11/26/Washington-D-C-group-sues-Port-Authority-over-refusal-of-Don-t-believe-in-God-ads/stories/201311260144
D.C. group sues Port Authority for refusing to run nontheist ads
http://triblive.com/news/adminpage/5152467-74/authority-ads-run#ixzz2lp39v8ro
Port Authority Sued By Non-Theistic Group Over Ad Space
http://pittsburgh.cbslocal.com/2013/11/27/port-authority-sued-by-non-theistic-group-over-ad-space/
Atheist Billboards: Pennsylvania Non-Theist Organizations Sues Port Authority for Refusing to Run Advertisements
http://www.hngn.com/articles/18247/20131127/pennsylvania-non-theist-organizations-sues-port-authority-for-refusing-to-run-advertisements.htm
Group sues Port Authority over nontheist ads
http://www.wtae.com/news/local/allegheny/group-sues-port-authority-over-nontheist-ads/-/10927008/23184020/-/k844pz/-/index.html
Atheists Sue Pittsburgh's Port Authority for Rejecting Godless Bus Ads (Original Press Release)
http://unitedcor.org/national/news/atheists-sue-pittsburgh%E2%80%99s-port-authority-rejecting-godless-bus-ads