With Miller High Life Logo Spoof: Become a Pi Life Man (or maybe it was "Live the Pi Life"
This year: "AEPi: A Cut Above The Rest" with a cartoony image of a moile standing over a baby sitting on a table with the CofA.
Next year: "Get Rich or AEPi Tryin' "
Ones I've heard about:
Do the Jew (with mountain dew spoof)
Jesus Saves, Moses Invests
Making Mothers Proud since 1913 (or your chapter's founding year)