User blog comment:Sonic & Scrab Master/Knuckles Briefs and Sonic Shorts/@comment-1645715-20100701174823

Here. You could also try googleing it. I believe there's a link to the Summer of Sonic website. There are also many extras you can click on in the shorts. So far, it's only in 2 and 4. There are also small clips that are after the credits. Like in number 1, if you click on Knuckles, he'll start to get mad and eventually punch the screen.