Ha ha! It's good to hear from a Rho Beta because I'm a Delta Lambda and going through the same questions!
My chapter does the Roses thing ("Roses to Bethany for being a good sister!"), and a book we pass around from sister to sister writing about how they have helped us (or about anything, really). One girl will start it and write to one sister who will write it to another sister and so on and so forth until the last chapter of the year where the last sister will write it to the chapter.
We also did the Loving Cup at our Red Rose Ball this year. It was hilarious! One of our sister's is a pottery major and so she made us this great Loving Cup and we filled it with water and passed it around, singing the song... we could not stop laughing and all the boys were taking pictures!
There are lots of things to do as everyone before me has said.