It appears to be a freemium typeface called Big Top, which itself is derived from Dan X. Solo’s Circustime (only appears to have been available on the CD that accompanied the Dover Circus book):
http://abfonts.freehostia.com/solopedia/solopedia-c.htm

Fontmesa’s Buckhorn comes close:
http://www.myfonts.com/fonts/fontmesa/buckhorn/