Police used teargas pepper spray, rubber bullets and LRAD "sonic weapons" against University of Pittsburgh students during the Pittsburgh G20 Summit. Many of the students were not part of any demonstration but bystanders, curious to find a mass of armed riot police on their campus.

http://www.youtube.com/watch?v=etv8YEqaWgA

http://www.youtube.com/watch?v=5NSsj4a6v5U

http://www.youtube.com/watch?v=W-TqMDthnEo