I might be about to get the ACLU to go after my school

[Okay, maybe Mike Johnson is a competent parliamentarian.]

Equality club sounds like a much better, and more inclusive, name. Not everyone who is non-het is a gay.

I went to a school that had a 'Queer-Straight Alliance', which was semantically preferable but just sounded bizarre.

[Okay, maybe Mike Johnson is a competent parliamentarian.]

I understand a club for gay students but what exactly is a "Gay-Straight Alliance"?

A club that both gays and straights join, I guess to show that they get along.  Colleges probably like that.

What do they... y'know... do, though?

Mostly talk about "gay issues," like coming out and discrimination and whatnot. My college's gay straight alliance ran a anonymous hotline for at-risk gay youth to call. Others plan "gay proms" and similar things.

Basically, it's just a collection of gay folks (and their allies) who work to make sure that at least someone, even if it's a dorky club, is acting in the gays' best interest.

Pretty much. They actually do really good, often actually pretty unobjectionable work, and a lot of them are self-aware as to the absurdity of the name.