While the girls are all standing on the field waiting to open their bid cards, all the sororities are waiting on their lawns for them to come running. Since my sorority's house is on Frat Row and not Sorority Row, we all meet right on the field and have the fraternity guy spectators hang a HUGE "Follow the Arrow to Pi Beta Phi" from the parking garage. Everyone knows where we are.
Then while the Bid Day activities are taking place at the house, senior sisters ride over to each new member's dorm, apartment, or house to hang door decs of a heart with angel wings. They're cute. And in dorms you can see which sorority everyone's pledging!