This what I think Superman's dreams are like sometimes.
The Story: "Time Signs a Death Warrant for the Justice League!" by Gardner Fox, Mike Sekowsky, and George Roussos. This story opens with a bunch of people from the future spying on a May, 1968 meeting of the Justice League!
Turns out that lockpick of licentiousness, the Key, has found a way to have complete mental control over the JLA! He sends a command to them in their Secret Sanctuary instructing them they are trapped, and in one hour they will all fight one another! For some reason, Superman, Wonder Woman, and Green Lantern are the least concerned.
Turns out a future Superman is in this meeting, not the "current day" one, so he...man, does this get complicated. Suffice it to say, Superman fights off the rest of the JLA, escapes the Sanctuary, and they go all fight the Key. Whew!
Roll Call: Superman, Batman, Wonder Woman, Aquaman, Flash, Green Lantern, Green Arrow, Atom, Hawkman
Notable Moments: Another time when there's no appearance--of even mention--of the Martian Manhunter. Weird.
The time travelling historians plot is cute, and was homaged by Gerry Conway fifteen years later, in JLA #206. But that's a little ways away...
This is Mike Sekowksy's last issue as penciller of the Justice League of America. Sixty-three(plus three Brave and the Bolds) straight issues, an amazing run, even moreso considering how dense a lot of these issues were. Sekowsky may not have had the polish and the brilliance of a Jack Kirby(who does?), but I think the sheer consistency gave the JLA a solid identity that helped establish the team and the book as one of the mainstays of the DCU.
Of course, sixty-three issues would look like nothing compared to what was next...