Insert your own butthole joke here. I'm still too floored.
Alrighty, first and foremost ASSUME ALL LINKS IN THIS POST TO CONTAIN CONTENT THAT IS NSFW! . I cannot stress this enough. If I didn't think blinking red text would incite justified rage, I'd put it in that. THESE LINKS ALL HAVE THE POTENTIAL TO HAVE VERY VERY NSFW CONTENT! So I'll try and summarize it the best that I can here.

Yesterday on the Discovery Channel 'Mythbusters' message boards, a questionable image started being spammed. The image contained what was claimed to be one of the hosts, Adam Savage, doing what I'm going to politely describe as a somewhat mild Goatse impression (DON'T LOOK IT UP IF YOU DON'T KNOW WHAT IT IS, FOR THE LOVE OF GOD). Naturally the threads containing said photo were quickly deleted... but of course not before plenty of folks had the chance to save the evidence.

Encyclopedia Dramatica already has a write-up, including a screenshot from the original chaos on the Discovery Channel message boards of a post from a concerned parent (copypastain' so folks won't have to click it):

"this is to whomever is posting the photos of Adam naked, my 11 year old son woke up early and hopped on the computer to come here to see what episodes are coming up (this is one of his favorite shows) and clicked a photo link (i wont post it here) but the link seems to contain naked photos of Adam Savage, he was terribly upset by these and I feel compelled to contact media sources for scarring my young boy. this WAS his favorite show, hes been crying all morning. It seems to me the names of these invaders are googleable and come back as members of www.ebaumsworld.com please look into this, and until i see an apology for this consider my family no longer viewers of Mythbusters OR ANY Discovery channel shows, if these are the kinds of perverts you put on air. thanks"

There are massive threads about it all over the web, including on Something Awful, ONTD, and Digg.com.

There's still heavy debate on if the picture is real or not, with folks pulling out their degrees in Photoshop all over the place and the blame being cast on everywhere from good 'ol Ebaumsworld to /b/. There has been no official statement from the Discovery Channel on the incident, and so far the hubbub seems to be confined to the internet. But oh, what a hubbub it is.

ETA: Added the 'concerned parent' quote from ED.

ETA 2: According to what's being said on the 'Discussion' page of the ED article, it's possible the 'concerned parent' screenshot was faked. Moreso, it's possible there never was any spamming of the Discovery Channel message boards. Making it quite an epic (and judging by the reactions around the web, successful) joke.