Welcome to GC!
We didn't really do chants for IM's when I was in school. But here's a chant we used on bid day:
Green, green, green and white, heard that is their cry,
Green and white is mighty right, so's the house of AEPhi!
So tell your folks and tell your friends you're not sad or blue,
'Cause you took a liking to AEPhi and we took a liking to you!
(It's catchy. I've been an alum for over 10 years and I still remember it
)
The last two lines don't really apply for intramurals, but the first two lines would make a great chant.