http://www.mspaintadventures.com/?s=6Homestuck is a multimedia webcomic written by Andrew Hussie, on the MSPAdventures website. It utilises panels, GIFs, animations, interactive segments, and dialogs. It is about 4 kids, who play a video game together.
It also has one of the most complex and elaborate plots of a literary work ever, full to the brim with Chekhov's guns, foreshadowing, and out-of-context spoilers. Its very hard to reveal anything specific about its plot without spoiling anything, but suffice to say, the video game has rather further-reaching consequences than you'd think. The story is split into '7' 'Acts', and its generally agreed that its a bit slow in the beginning, but picks up around Act 3-4. Initially, the author (Andrew Hussie) used reader requests when writing the next panel, but eventually that became too restricting for the story, so he stopped.
Here are a few really good songs used in animations:
Descend-
Black-
MeGaLoVania-
Cascade-
Sburban Jungle-
Umbral Ultimatum-
(had to find one without spoilers)
If you don't like Homestuck, I'd also recommend Problem Sleuth. Also written by Andrew Hussie, on MSPAdventures, its about a detective trying to leave his room. While Homestuck can be rather divisive, Problem Sleuth is just generally regarded as great.
Ill finish with a quote from a fan who was asked to sum up the comic in 10 words.
"Aliens, time travel, kids, game, buckets, death, apocalypse, kill Jack."