Well, I grew up in the '80s, but I'm not sure what theme you're going for. Perhaps you could try comic book characters- The Hulk and She-Hulk might be a cool pair. (She-Hulk was first introduced in the 1980s- but keep in mind that she and the Hulk are cousins, not lovers.
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Maybe a pair of break dancers or punk rockers would be the way to go. I'm sure someone on here might have a better clothing-specific costume to give you. I don't get that much into fashion to really know though. lol. Anyway- just make sure to have some good '80s music to listen to- and everybody have fun tonight! (everybody wang chung tonight.) 
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