40 Dress Up Party Themes Even Adults Can Rock I’ve catalogued a whole list for you to pick through so if you’re planning the ultimate dress up theme for work or throwing a summer party for adults only ( or anything in between), I’ve got you covered. Themed costume parties make for some seriously fun adult get-togethers, and they can be the highlight of your year if you choose the right one! In our family, we’ve got some milestone birthdays and important celebrations coming up so I’ve been brainstorming up the best dress up party themes for adults. I mean, I may not be interested in those particular details, but I still like a lively event! Why do kids get to have all the fun with the bounce houses and the face painting and what not?