"Spike & Mike's Sick & Twisted Animation Festival." It still limped along for a bit in the 2000s (I still have my 3D glasses from "HERE COMES DR. TRAN" from around 2002), before (apparently) being done in by broadband and YouTube, but is there anything more '90s? If you lived in a quirky medium to large city, once a year you'd head down to some independent theater to stand in line to watch shorts like "South Park's" "The Spirit of Christmas" or "Frog Baseball" with Beavis & Butthead.
Wiki tells me that there was originally a "Festival of Animation", that started in 1977 and "...Sick & Twisted" spun off in 1990, with "Festival of Animation eventually being killed off. At some point in the 2000s they added another festival for non sick & twisted animation and the Wiki article treats it like it is still a thing, but down in the endnotes the external link to the official page is archived by the Wayback Machine from 2014.
Oh, and it started in La Jolla, so while I somehow missed going to Comicon when I was stationed in SoCal in the early 2000s, I did see the season premiere of the "Sick & Twisted Animation Festival" at least once.