All other (known) shows that John played at least one song at. There are more Thelonious Monster shows from right before he initially joined RHCP in 1988 and details on most things happening throughout the 1990s and 2000-2003 are before our time*, from the days Internet was not what it is today, and therefore they might be sketchy.
Black Knights @ Low End Theory Date: May 28, 2014Black Knights debuted two new songs off The Almighty and performed Medieval Chamber at Low End Theory in LA...with John as their sound man. This was his first onstage appearance in almost four years.
Swahili Blonde @ The Echo Date: July 10, 2010Present on all studio recordings up to 2015 thus hyping the up-and-coming band; John joins Swahili Blonde onstage for one song, Dr. Teeth, at their album release party.
Them Hills @ The Troubadour Date: October 3, 2008Them Hills closed a night at the Trobadour headlined by then up-and-coming WarPaint and John and Josh joined them on stage for a cover of New Order's Ceremony.
Troubadour Jam '08 @ The Troubadour Date: September 4, 2008After the Rock4Change event was cancelled despite the hype surrounding it due to low ticket sales; John, Josh, Flea and Stella Mozgawa filled a spot after WEAVE! and WarPaint (which Stella was not a member of at the time) at the Troubadour thanks to last-minute line-up changes.
Kenan Bell @ Spaceland Date: June 9, 2008At the end of Kenan Bell's Monday night show (which Josh Klinghoffer played throughout), John jumped onstage during the last song, Good Day. He initially played keyboard, but then he switched instruments with Jon Siebels (formerly of Eve6) and played guitar.
Shavo Odadjijan's Birthday / AcHoZen 1st single promo @ The Roxy Date: April 22, 2008John rocks the stage at Roxy for Shavo Odadjijan's birthday party and the promotion of the Armenian-American bassist band's first single; alongside a very versatile group of musicians.
Dave Gahan All Star Band @ Henry Fonda Theater Date: May 11, 2007Dave Gahan of Depeche Mode assembled an all-star back-up band to perform a cover of Policy of Truth at the Third Annual MusiCares MAP Fund Benefit Concert To Honor Chris Cornell And Jeff McClusky. The band? Victor Indrizzo, Vincent Jones, Martyn LeNoble, Josh Klinghoffer and, of course, John Frusciante.
Chad Smith & friends @ Federation Square, Melbourne Date: April 11, 2007Commonly known as the "Federation Square Jam", this event was filmed for Chad Smith's Eastern Rim DVD. The jam band featured John, Josh, Flea and the star of the day.
Mike Watt and the Missigmen @ Globe, Stockholm (2) Date: December 12, 2006For the last of their shows with the Red Hot Chili Peppers in 2006, John joined the Watt and his band for a total of four songs.
Mike Watt and the Missigmen @ Globe, Stockholm (1) Date: December 11, 2006For the fourth time in a row, John joined the band onstage for one song.
Mike Watt and the Missigmen @ Forum, Copenhagen Date: December 9, 2006For the third time in a row, John joined the band onstage for one song.
Mike Watt and the Missigmen @ Stadthalle, Vienna (2) Date: December 7, 2006Just like the night before, John joined Mike Watt, Tom Watson and Raul Morales for one song; this time expected to do so by the audience in the Austrian capital, as the word got around...
Mike Watt and the Missigmen @ Stadthalle, Vienna (1) Date: December 6, 2006First out of five times, John jumped onstage after tweaking some of his equipment to join Mike Watt's band for one song.
The Mars Volta @ Air Canada Center, Toronto Date: September 25, 2006The Mars Volta were opening for the Red Hot Chili Peppers for some of the USA and Canadian show and at the first night in Toronto, vocalist Cedric Bixler-Zavala pulled out and John jumped in to help his friends and improvised with them all set long.
The Mars Volta @ Santa Barbara Bowl Date: October 14, 2005John joined The Mars Volta in Santa Barbara for a single song, L'Via L'Viaquez.
The Mars Volta @ Long Beach Arena, Long Beach (2) Date: August 5, 2005John joins The Mars Volta onstage during L'Via L'Viaquez.
The Mars Volta @ Long Beach Arena, Long Beach (1) Date: August 4, 2005John joins The Mars Volta onstage during L'Via L'Viaquez.
The Mars Volta @ Greek Theater, Los Angeles Date: June 4, 2005John joins The Mars Volta onstage during L'Via L'Viaquez.
Yoko Ono @ All Tomorrow's Parties, Camber Sands Date: April 24, 2005Yoko Ono, Sean Lennon and Vincent Gallo closed the second weekend of the 2005 ATP festival, curated by the later. John joined them onstage and made the jam quite memorable.
The Mars Volta @ Personal Fest, Buenos Aires Date: November 5, 2004John travels to South America with TMV and joins them onstage during Drunkship of Lanterns. Otherwise, he does his best to appear incognito.
The Mars Volta @ Sue Festival, Santiago de Chile Date: November 4, 2004John travels to South America with TMV and joins them onstage during Drunkship of Lanterns.
The Mars Volta @ Wiltern Theater, Los Angeles (2) Date: May 13, 2004John joined The Mars Volta onstage for Take The Veil Cerpin Taxt.
The Mars Volta @ Wiltern Theater, Los Angeles Date: May 6, 2004John joined The Mars Volta onstage for Take The Veil Cerpin Taxt.
Vincent Gallo @ Royal Festival Hall 2004 Date: April 5, 2004PJ Harvey and John joined Vincent Gallo and his band (Jim O'Rourke and Steve Shelley) onstage for a, said by many, gorgeous performance of Moon River. Otherwise, this was a rare occasion where Gallo performed his entire 2001 album "When" and a separate single.
Vincent Gallo @ ATP 2004 Date: April 3, 2004Vincent Gallo played at the ATP Festival night curated by Sonic Youth and John & Josh were his backing band. The entire performance was an improvisation with no prior rehearsal.
Blonde Redhead @ Glasshouse, Pomona Date: March 21, 2004After he opened for the band with one of his experimental performances, John joined Blonde Redhead onstage at some point.
Pearl Jam @ Santa Barbara County Bowl Date: October 28, 2003During their benefit performance to raise funds for the John joins Pearl Jam onstage as the third guitarist for covers of two Ramones' songs - Daytime Dilemma and I Believe in Miracles; and then for the six-guitar showe closer, a cover of Byrds' So You Wanna Be a Rock'n'Roll Star.
The Mars Volta @ Northsix, Brooklyn, New York Date: May 21, 2003The first out of quite a few times John would join his afro prog-rock friends onstage, this time for the encore song, Cicatriz ESP.
De Facto @ Long Beach Date: August 18, 2002John joined the short-lived dub band that existed before The Mars Volta and after At the Drive-In for a long improv based on their song Cordova.
New Order @ Landsdowne Road, Dublin Date: June 22, 2002New Order opened for the RHCP at their biggest gig before Slane and John joined them on stage for a cover of Joy Division's Transmission.
Moby @ Blockbuster Pavilion, San Bernardino Date: August 5, 2001For an one-time performance of their former band Joy Division song New Dawn Fades, New Order teamed up with Moby, Billy Corgan and John, who taught Bernard Sumner and Peter Hook how to play their own song again after 18 years in the dressing room. This later ended up being mixed by Moby for the soundtrack of the 2002 Madchester-chronicling film, 24 Hour Party People.
Darby Crash Tribute @ Whiskey A-Go-Go Date: December 19, 2000At the end of year 2000, John held a private show backed by Flea and Josh Klinghoffer as a tribute to Darby Crash, the late singer of Germs.
The Bicycle Thief & Blonde Redhead @ The Glasshouse Date: December 1, 2000John joined Blonde Redhead onstage and jammed with them during the encore.
Joy Division Tribute @ Spaceland Date: October 10, 2000Still, an one-time Joy Division cover band consisting of John, Flea and Josh performed a single show at Spaceland in 2000. John did his best impression of the late Ian Curtis and one of his guitar heroes Bernard Sumner, both musically and style-wise.
H.A.T.E. @ Club Lingerie Date: March 16, 1991H.A.T.E. had more visitors at this show, once it was known that John and Flea are indeed a part of the band (rumour says that previously many people assumed they were just lookalikes!).
H.A.T.E. @ Second Coming Date: August 20, 1989H.A.T.E.'s low-key gig - sweaty, barely dressed, with a lot of covers played.
Thelonious Monster @ Cal State Fullerton Pub Date: September 23, 1988One of the concerts John played with Thelonious Monster prior to joining RHCP. The concert was divided in two sets and, apart from guitar, John also sung on Gut Feeling.
*As in, this site was opened in 2004. Feel free to drop a line; if you have any corrections.