I mentioned this in a previous comment, but I really like this Fixit Clinic poster from the Boston area:

https://allevents.in/mattapan/fix-it-clinic/200026636930752

It's not a ground-breaking paragon of graphic design but it communicates what it needs to communicate: what, when, and where. And crucially, it has photos showing what the event looks like. Photos of real people fixing real things.