I cleaned my glasses several times...

... and I was still confused what these people were doing in front of my window:

At the same time it was super loud so I couldn't really ignore it (but it sounded fun, so I was okay with it ;)). But people were wearing these super protective suits and you can do a 360°-overhead-turn with it! They tried to play soccer which worked out (you usually crash a lot while playing soccer and these costumes are an invitation to do that ;)).