Here's a few from my school:

If you can't go greek, go TKE
Chi-o=Chi-ho
AOPi=AOPig
DZ=Easy D-Z or Sleazy D-Z
Tri Sigma, everyone else has.
ADPi=ADpoo (long story...)

All of the sororities and frats have certain reputations and most of the stuff above doesn't even coordinate with the organizations reputation.