ooOoo
A total ice breaker that is used best when things get silent.  Often used after someone says a statement and there is small break between what they have to say.
Example 1
Professor:"Our next test will be on the 26th, it will cover chapters 4,5, and 6."
Student:"ooOoo!"
Professor:"What's that?"
Student:"Oh nothing"

Example 2
Person 1:"That Jade girl is so hot"
Person 2:"ooOoo"
Person 1:"I am glad you agree.."