One of the greater aspects of the Flash community is how it can be tied together with so many people. All nerds or geeks, all appreciating one video game franchise or another. And so, geeks who love the same franchise get together and, instead of making one long video with their collective effort, they instead each make a smaller video and group them all together to get what we call "Collabs".
Obviously, "collab" comes from "collaboration", so it's all about gatherins lots of fans from a series and just cracking jokes about it, in Flash animation form.
The most notable example of such is the Sonic collabs, named Sonic Shorts, which went on for SIX videos, with about a hundred miniature videos made about the franchise and grouped in those videos.
Look out, however; some of the comedy "could potentially" be Not Safe For Work. After all, this was made by different artists with different comedy styles and different senses of what comedy is, so some jokes could be "offensive" or just plain bizarre or yucky. But it's mostly the language, and also some of the non-seen scenes. It's not "too" bad.
You can watch all of them in this Youtube selection.
Heck, even KNUCKLES gets one later.
After the popularity of the Sonic collabs, the Mario fandom replied with this. http://www.newgrounds.com/portal/view/429242 A Mario collab!
And a little later, the Kirby collab... http://www.newgrounds.com/portal/view/542162