If you're going to do cosplay, don't dress up as some manga character with a purple sash - it's too easy. If you're going to do it, do it with S.T.A.L.K.E.R.
Thanks to Isaiah who sent us a link to this Russian site not only of STALKER fans taking the game into the real world at Chernobyl, but also some really fantastic photography. It's well worth a look.
If you want to get a bit more understanding of what's going on (but not much), here's the Google translation of the page. EDIT: And with even better translation from Xander77 in the comments below!