I think the Grease would be good for Gamma Phi Beta (or Phi Mu or DG) because you could still be the "Pink Ladies". You could make Poodle skirts with Cresents (or letters, or a local mascot, if you have one) instead of Poodles. Poodle skirts are actually very easy to make...I made one once for a costume party (only I used a frog on a lilypad instead of a poodle
).