I'm WAY too young to remember Old Chicago, but from looking at these old commercials, it looks like it was an indoor type of amusement park, kind of like what Camp Snoopy or I think it's Nickelodeon Land at Mall of America. Am I right?
@Brian1978 - Well, they did air the same commercial that day (almost - see below) but the one posted here did come from an entirely new and undiscovered Bozo's Circus episode that I found, which aired on Wednesday, July 11th 1979.
By the way, the version of this ad that did air during Chicagofest interestingly has a slightly different opening title card - all in white versus the oscillating multi-color seen here. Take a look.
This was the second commercial during the first break of the special, "Bozo at Chicagofest" taking place on August 3rd, 1979. I will always think of it being after the commercial for Dispensa's Kiddie Kingdom.
Felipe Rose (the Indian) scarily resembles the Twi'lek dancer from Return of the Jedi who's dumped into the Rancor pit by Jabba, the way he's moving around on stage with the headdress swinging behind him.