I guess this is the better of the two circus threads for Windjammers linkage:

http://www.circusmusic.org/

Closest thing to an 'official' site out there. They also have a Facebook page. They partnered with EBSCO sometime back so you should be able to find back issue ecopies of their newsletter Circus Fanfare through your school or major public library.

And the 'generic' wiki:
https://en.wikipedia.org/wiki/Circus_music