There is an academic, Jeffrey Schwartz, who presents the argument that chimpanzees are not the closest ape to humans:
http://scienceblogs.com/gnxp/2009/06/the_red_ape_resurrected_willi_1.php

Returning bonobos to the wild - [Duke anthropologist Brian Hare]

http://www.sciencedaily.com/releases/2009/06/090615171523.htm

The last common ancestor of humans and apes was capable of laughter .. er .. maybe

http://sciencenow.sciencemag.org/cgi/content/full/2009/604/1?rss=1

See article
By Virginia MorellScienceNOW Daily News4 June 2009

Also:
http://uk.news.yahoo.com/5/20090604/tuk-how-laughter-links-humans-with-great-45dbed5.html

http://news.bbc.co.uk/1/hi/sci/tech/8083230.stm

Concerns the work of:
zoologist Marina Davila Ross of the University of Portsmouth in the United Kingdom and colleagues.