Greek Sing (on my campus) is an annual event sponsored by Chi Omega and Kappa Alpha, where all the fraternities and sororities prepare a 5-minute song and dance type thing to perform and be judged on. There's also a banner contest, too. It's a really big deal here, and a lot of non-Greeks buy tickets and come watch, too. Everyone, even the performers, have to buy tickets, but all the money goes to the Make-a-Wish foundation so I don't mind paying.
Be careful, though...last year, TWO other sororities had the same cowgirl theme we did, and the very same songs. It was horrible. We didn't know, of course, because everyone keeps it a secret. This year, the people in charge decided to have all the participating groups turn in a paper a few weeks in advance stating their theme, so that there wouldn't be a repeat incident. Well...someone must have dropped the ball somewhere, because we were horrified to find out that another sorority was doing our Vegas theme! Well, maybe not horrified, exactly, but we were surprised and very PO'd. Groups who have the same theme never win, so we were pretty upset after all the work we'd put into it. But we did a good job and showed them up, so I'm still proud.