Found this gem in the metro east: https://www.google.com/maps/@38.6417392,-90.1543387,3a,26.8y,191.88h,86.94t/data=!3m6!1e1!3m4!1svEz4LNGGprBSuA9Y1_mNNg!2e0!7i13312!8i6656
I don't know about funny but there was something surreal about the graffiti I found in Goffs, CA on old US 66 back during 2016:
https://flic.kr/p/S3W65f
The self-aware part is humorous, but it looks more like regular handwriting than a coherent part of the actual graffiti.