It?s not clear what will happen at this year?s Mifflin Street Block Party, so Julia Mercer and her roommate are taking no chances. They live on the 400 block of West Mifflin Street ? party central ? and after last year?s trouble-filled bacchanalia, they?re planning to lock all their valuables in their bedrooms, including their dishes and the TV. ?We?re kind of freaking out,? Mercer, a UW-Madison junior, admitted to police officers who stopped by her house Wednesday to talk about rules for the May 5 event.