Next event:

Atlanta United Viking Clap

You’ll hear a double drumbeat, followed by a pause, then clap your hands overhead a single time and yell a single letter, to spell “ATL”
Drumbeat: -----A!
Drumbeat: ---- T!
Drumbeat: ---- L!
(repeat faster & faster until everyone just claps & yells)

Usually around minutes 42 and 80; everyone in SS raises their hands overhead, followed by everyone in stadium.