Throughout their career, Sonic Youth did a number of shows with no fixed set list and no "songs" performed, instead offering an improvised journey of sound and noise, often with special guests rounding out the din. This is a list of all such shows with some brief details. I've also included some "rock sets" that featured a notable improvisation. Click the show date for more info!

The band provided sound effects and incidental music to three performances of Mike Kelley's piece Plato's Cave, Rothko's Chapel, Lincoln's Profile. Part of this performance was released on the "Tellus #18" compilation. A full video circulates.

In town for 3 shows at the Fillmore promoting A Thousand Leaves, Sonic Youth spent one afternoon creating music in the vein of their then-new SYR series, with William Winant and Jim O'Rourke sitting in. Jim had collaborated with SY on the recent SYR3 project, and this in-store noisefest led to SYR4 which featured heavy involvement from both William and Jim.

After performing their standard A Thousand Leaves festival set, the band was joined by Spiritualized for a 12-minute jam.

This was the first performance of the SYR4 material. The band was joined by Jim O'Rourke, William Winant, Wharton Tiers, and Takehisa Kosugi to replicate the largely improvised scores, some of which were published in the show's program. Thurston, Kim, and Lee all performed in solo combinations to open the show. The album would be released in November, and they would do a proper tour of the material in June of 2001.

This was a very interesting set, premiering two new pieces (later released on NYC Ghosts & Flowers as "Free City Rhymes" and "Renegade Princess") before the only other 1999 performance of an SYR4 piece - James Tenney's "Having Never Written a Note For Percussion". Following this, Thurston introduced "Expressway To Yr Skull", but the band launched into a 20-minute improvisation before beginning that song (which also ended with its typical lengthy improvised outro). I always assumed this was just the band having fun, but a printed set list that recently surfaced actually indicates this piece was identified on the set list as "Composition". After "Expressway", the band returned for a single encore of "Stil".

This evening was a collaboration between Sonic Youth and Brigitte Fontaine. A long-promised SYR project has yet to surface, but this show demonstrates what could have been - 80 minutes of drawn out improvisation with occasional vocals from Kim and Brigitte. Areski also guests.

These 3 shows were advertised as "SYR: Perspective Musicales" events while the band was on tour with Pearl Jam. While all of these shows featured SY's standard NYC Ghosts & Flowers set, they also featured exciting combinations of various band members as well as solo performances. I'm including them here due to some of the heavily stacked combos such as Lee/Jim/Steve/Thurston improv over films and Kim/Steve/Jim doing SYR5 style jams. It was becoming increasingly common for the individual band members to do solo/improv gigs (check this section before I gave up!) but these shows were a rare instance of them collaborating in different ways while still presenting themselves as Sonic Youth.

Likewise, Kulturbro 2000 was a week-long event that opened with 2 proper Sonic Youth performances (playing some pretty curious sets!) followed by a week of individually curated evenings containing some pretty wild moments. The first evening was released as the Mats Gustafsson disc Hidros 3. All of SY were present for this piece. The next night featured various combinations led by Thurston. Jim's night featured a performance of "Louie, Louie" with Kim on drums, Thurston on horns, Lee on piano, Steve and Mats on guitar, and Jim on saxophone! Lee's night was a single improvised piece with players entering and exiting at various intervals, including all members of SY. Steve's night featured a similar concept. Loren Mazzacane Connors' night featured, among other things, Thurston, Steve and Mats performing an acoustic version of "Mildred Pierce"! Kim's night closed the festival and featured a number of odd pairings as well as another performance by the Kim/Jim/Steve psuedo-SYR5 trio.

A year and a half after releasing the album, the band (along with primary collaborator William Winant) decided to do a proper tour for the SYR4: Goodbye 20th Century material, playing 10 shows in Europe in June 2001. Two of these shows were standard SY "rock sets", one was a very non-rock festival set, and the remainder were full-length SYR4 gigs with a slew of guests along the way. Album pieces like "Burdocks" "Six" "Treatise" "Having Never Written a Note For Percussion" and "Four6" were played nightly, along with another Steve Reich work "Clapping Music" - performed by Steve and William Winant. Konrad Boehmer's "Echelon" received a single performance in Amsterdam. Few lucky audiences were witness to the total destruction of an upright piano, as glimpsed in the digital bonus content on the SYR4 enhanced disc, for the occasional performance of "Piano Piece #13". Kim did vocal duty on "Voice Piece For Soprano", which was spread out between the first few pieces. Beyond that, each SYR4 gig ended with 3 Sonic Youth tracks: "Side2side" "She Is Not Alone" and "NYC Ghosts & Flowers". A Barcelona festival set began with a lengthy improvisation which led into "She Is Not Alone", followed by "Four6" and a finale of "Side2side". Various guests included Christan Fennesz, Richard Edson, Günther Müller, Marina Rosenfeld, Dean Vandewalle, Jean Marc Montera, Peter Rehberg, Laetitia Sadler, and Dean Roberts. The first night of this tour was released officially via bandcamp.

Having performed their Murray Street tour set the previous day, SY used their second Fuji slot to create a blistering wall of noise with Yoshimi from the Boredoms.

A few days later, the band opened their North American Murray Street tour with a very bizarre in-store, performing five-minute ideas they claim to have conceived on the way there. Such ideas include Steve perched upon Thurston's shoulders, deflecting moon pies thrown by the rest of the band with a squealing guitar.

SY improvised alongside a showing of Stan Brakhage's films, joined by Tim Barnes. This was later released as SYR6.

Following their Nurse tour set at the Ogden Theatre, SY joined openers Wolf Eyes for a set of searing noise at Monkey Mania.

After a standard Nurse festival set the previous day, the band took the opportunity of a second Roskilde slot to show off another side of their music, presenting an hour-long improvisation split into 5-minute intervals with players entering/exiting per a pre-determined script. The band was joined by Mats Gustafsson and Merzbow for this set, which was released as SYR8.

Prior to their Daydream Nation/Rather Ripped heavy headlining set, the band played an improvisation with Jean-Marc Montera, Michel Doneda, and Mats Gustafsson. These three also joined for "Expressway".

These four performances were a celebration of choreographer Merce Cunningham's 90th birthday. Sonic Youth performed a soundtrack for the dancers, along with separate accompaniment by John Paul Jones and Takehisa Kosugi. SY prepared 9 concepts to be played in different orders over the four nights, including a 3-minute idea called "SMASH GRIND DISTORT", 6 minutes of "FILE/METAL" toolin', and 10 minutes of likely EG# contender "EXPWY".

The band performed an improvised set with Bill Nace sitting in for Lee, who was at the Cannes Film Festival.