Check out this moped enduro race in Switzerland, I just saw this the other day and had to share it with you guys, looks like an absolute blast. Everyone is suited up in goofy attire or special machines for this event. Unfortunately, I can't embed the video so you will have to follow the link but it is definitely a fun one! I can't believe it's taken me this long to find out about it.
Yeah, there are all kinds of these groups throughout Europe. They are diverse too, and range in age from 16 to Grandpa/Grandma who originally purchased their Mobilette/Puch/Zündapp/Vespa/whatever in 1961. Some of these events/groups are small, others number in the hundreds. Lots of video on YT. Greetings!