He played in trio and quartet settings and eventually formed and recorded with the improvising iconoclasts, Strange Attractors, which used only verbal texts for its spontaneous, electrifying performances. Hall's interest in William Burroughs eventually led him to composing a series of pieces called Hallucinations: Music and Words for William S. Burroughs (Leo) that he recorded with eleven musicians, featuring trombonist Roswell Rudd.
In 1998 he assembled one of his current groups, the quintet OutSource with guitarist Michael Occhipinti, drummer Barry Romberg, bassist Michael Morse and vibraphonist Allan Molnar. This group recorded and performed with Rudd, producing a CD released in 2001, The Roswell Incident (Leo). Recently, Hall has assembled a genre-defying eleven-piece group, redShift, consisting of two turntablists, two bassists, two guitarists, a percussionist, vocalist, a drummer, and his own woodwind arsenal, tam tam, electronics, and spoken word. He also leads Sonora an improvising chamber group with violin, cello, contrabass and woodwinds.
Hall is also a member of the Woodchoppers Association, an expansive free improvisation orchestra, Powerbuch, a spontaneous composition quartet, the dadaist Big Band Massacre and it a guest with The Cronics, a power rock trio, and the Free Work Band, a trumpet/bass/drums jazz trio.
In June, 2001, he organized and produced (416) 2001, a festival of creative improvised music involving nearly eighty musicians and multiple venues, as well as conducting the Here To Go Arkestra. Lately, Glen has combined forces with such formidable instrumentalists as trombonist Ray Anderson, drummer Gerry Hemmingway. bassist Dominic Duval, and saxophonist Sabir Mateen, as well as forming an on-going trio with Sonic Youth guitarist Lee Renaldo and drummer William Hooker.
As for the future, Hall is currently developing music for performance, recording, film and CD-ROM involving multimedia images, electroacoustic sounds, spoken word, and improvisers from different fields of music.