When you see street preachers holding up signs or handing out tracts, there can be a wide variety of beliefs represented. Something most seem to have in common is preaching against sin. You'll often find them at crowded areas with a lot of foot traffic. They especially show up at public events that endorse or even celebrate specific sinful actions or lifestyles, like Pride.
One approached me and handed me a tract, and I asked him several questions and discussed points about his message. Below is the audio of the conversation. This will have a lot of background noise, with variance of how loud it gets, so you'll have to listen carefully.