Critical Mass happens in Ottawa on the Last Friday of every Month. The meet up is in Confederation park at the fountain (corner of Elgin and Laurier) at 5:30 pm. The mass leaves at 6:00. The mass goes through out the winter getting only a handful of hardcore participants (5-10) and springs to life in the spring (May) getting 60-75 participants on a nice summer day. The facebook group Ottawa Critical Mass allows members to share information and pictures. There is also an older blog which is sometimes used for the same purposes.