FishermanThis one is really simple - wear rubber boots and usuall pants or jeans. You can also wear real fisherman pants with high boots if you have one. You can make a simple cardboard fish and put it on a stick (which can be very simplified fish hook). And I think you'll be really funny and unique.
Men dressed like a womanAnother really funny and simple costume os men dressed like a woman. You can buy inexpensive wig and shoes (let them be large enough for you) with high heels (but not too high). Then add some simple shirt or dress. And how about make-up? You don't really need much, just some lipstick, eye shadow and mascara.
BallerinaMen dressed like ballerina can be really funny too. You can buy premade costume or make it at home. Well you won't really make it, just put some things together. You can use pink outfit (let it be very gentle and light pink) and buy pink shirt, tutu skirt, some ballerina shoes (I believe that some simple pink shoes will do to). You can even put on a scarf on your head to cover your hair or a little pink hat.
GeekMy last funny costume suggestion is geek. Isn't it simple? Just comb your hair, put on some glasses (large ones), a geeky shirt and pants and you are done. And you can bring some books too if you wish.
These were my suggestions for funny and simple costumes for men and I hope it helped you to make your own costume.
Images by Pippi Dust.