Costume Party Hats Please Help Me With Costume Party Ideas?

Please help me with costume party ideas? - costume party hats

I rescue party for a friend who is dressed not know what to like.
There is no problem, but it's a costume party.
I do not want to buy a costume.
I was thinking of dressing like a silly boy, because I am a little funky with a propeller hat and long socks to have:)
What do you think?
If you have an idea, please help me, because I would really appreciate it! Thank you!