If you have not heard the term, COSPLAY, it's slang for "Costume Play". It means people who enjoy making and wearing costumes in public, usually in the hallways and meeting rooms or public areas around Science Fiction, Fantasy, Comics conventions. These get togethers have formal "costume contests" where people can and do compete in many categories from little kids to amateur to advanced expert or even Master Costumer! There are Guilds and regional and national costume competitions annually for Master Costumers etc.
You can enter a competition as a "fun" costume, non competing, sometimes called a "hall costume". Walking around and interacting with people while in such "just for fun" costumes is called "Costume Play" or COSPlay. Recently teams or groups of people get together to represent a Tableau of Costumed Characters from their favorite media, and they might even perform choreographed dance routines or act out skits. It's alot of fun.
Twenty years ago I won a few competitions with my Klingon Admiral costume as part of a group, but now if I were to wear costumes at an event I'd only do it for fun, CosPlay, just to amuse myself and perhaps give someone else a smile. So that is why you see me post pictures of myself as a Klingon. :)
