I'm really not a DC fan but I've always loved the animations. Next to The Spectacular Spider-man, the Batman and Superman animated series' were the best animated adaption to a comic ever. Before those however, we had the little joke that was Super Friends. The little kiddy version of The Justice League will always remain a classic in the hearts of us, growing up in the 90's, though you can't deny, looking back at it from an adults perspective, it was total crap. Thank goodness we had the actual Justice League cartoon years later to make it all better.
Apparently though, DC, or maybe even a random fan, decided to combine both series' and brought about this little masterpiece. Ah, the nostalgia. Unfortunately, no Aquaman though. Don't know why they'd leave out such an essential character.