Audiences at shows put on by the troupe were often quite hostile toward the performers. After years of trying to appease the crowds with traditional performance styles, Riggs began to request input from them. As an example, he might ask "Who do you hate in this town?" If the audience replied, "the mayor," the performers would quickly improvise a scene about the mayor. However, at the time, improvisation was a word primarily used to describe the actions of jazz musicians. Riggs was an admirer of jazz and avoided using the term himself, preferring the phrase "instant theater." Later, a New York Times critic called Riggs' performances "word jazz," while members of the Second City troupe visiting in the 1960s and 1970s referred to the shows as "spot improv."
One year, the booking agent for the troupe stated that he couldn't find anyplace willing to take the performers. In order to keep skills strong, Riggs rented a street-level space in New York City where group members could practice. People walking by could see what was going on by looking through the window, and passers-by soon began to offer money to watch rehearsals. Riggs soon booked a venue and put on a regular show.
The famous critic Walter Kerr was an early attendee, and was amazed by what he saw. He held off writing a review for three weeks because he couldn't believe that the performers were actually taking in the audience's ideas—Kerr was convinced that group members were calling upon accomplices for input and were using pre-arranged material. After realizing the authenticity of performances, he wrote a glowing review.
The group began touring and eventually settled in Minneapolis in 1958. They were originally at a site called "Dudley Riggs Café Espresso" on East Hennepin Avenue where Riggs operated the first espresso machine in the state. After the café moved to South Hennepin in Uptown in 1965, claims of "the first espresso machine west of the Mississippi River" were also made. (Incidentally, the Uptown neighborhood now proclaims that they have more coffee shops per capita than Seattle, so Riggs may have been influential there as well.) The name was finally changed to "Brave New Workshop" at the same time.
Riggs opened the Experimental Theater Company (E.T.C.) in the Seven Corners area of Minneapolis next to the University of Minnesota in the early 1970s. This theater provided a wider range of material including stand-up comedy, variety shows, and specialty acts.
A number of famous performers started at the Brave New Workshop, including regional natives Louie Anderson and Al Franken, and writers such as Pat Proft, television executive producer Linda Wallem, and scriptwriter and producer/director Peter Tolan.
There was some sharing of experience and technique between BNW and Second City in Chicago. Del Close worked with Riggs for a time, and members of both troupes were regulars at each others' shows when traveling.
After operating it for 39 years, Riggs sold the Brave New Workshop in 1997 to Mark Bergen, John Sweeny, and Jenni Lilledahl, though Bergen eventually moved on to other projects. Sweeny and Lilledahl still operate the theater, and have made some changes. Their focus is more on long-form improvisation, while Riggs had always been more focused on shorter individual sketches.