A terrible (but I can see the humor in it) one, thats not exactly greek related is the t-shirt a couple of guys in XYZ fraternity decided to make for Welcome Week/Move- In. It was something to the extent of

Freshman Girls (on the front)
Get Em While They're Skinny (on the back)

It made headline news in the school paper and people talked about it for months. People started blaming the whole XYZ fraternity, even though most of the members had no clue about it.