Where Gay, Lesbian, Bisexual, Transgendered teens sit during lunch in high school. This table is a safe haven for them to feel protected and have a sense of belonging. This can vary to more than just one table. i.e. Goth gays, punk gays, popular gays, athletic gays.
Marshal thought it to be a good idea to sit at the gayble because there was no where else he felt comfortable to be himself.