|Gig not listed on GBV gig itineraries posted online but mentioned in this May 15th, 1997 Boston Phoenix article: http://www.bostonphoenix.com/alt1/archive/music/reviews/05-15-97/WEEZER.html
Article text: May 19, 1997 - Weezer play the Phoenix/WFNX Best Music Poll Festival on Lansdowne Street, May 19, with Reel Big Fish, Nerf Herder, Guided by Voices, G. Love and Special Sauce, Sloan, Trona, Guster, Gigolo Aunts, the Gravel Pit, Groovasaurus, Bim Skala Bim, Barrence Whitfield, Down Low Connection, Combustible Edison, Four Piece Suit, and Amazing Royal Crowns. It all starts at 6 p.m.
Gig was originally thought to be Axis but later confirmed to be Avalon by a few people that were there including Mike Gioscia, who said "Yes.... Avalon, I put them on stage". This japanese review also mentions Avalon: http://www.afropunx.jp/humming/live.cgi?action=list&artist=Groovasaurus.
Gig also confirmed by Doug Gillard with the following comments:
"I remember John P., Don Depew and I flying in, getting up to our dressing room area just a half hour before playing, and there was Peter Wolf from J. Geils band sitting there talking to Bob. He was a fan. When we left the venue, G. Love & Special Sauce were on stage in the street."