You could go as Del Boy…you have a few options to make it a little bit more funny;
– wear a cheap raincoat
– get hold of an old VHS video recorder to carry about with you
– get hold of some cheap watches and stick them to the inside of the raincoat
– get a blow up doll with ‘Caution – Flamable Gas’ written on it
– get some big cigars
– bring your own cocktail glass with umbrellas and other stuff in, and insist on drinking Cherryaid/7up and Malibu
– get hold of a cheap suitcase and fill it with crap and try to flog it to people
A friend went to a Hawaii party dressed as Magnum PI, but he also made a red car out of cardboard which he wore at waist level. You could try that if you can be bothered to make a car.
If you’re feeling lazy and want to look relatively sensible, you could go as someone from The Specials – get a 2nd hand suit that looks 80’s ish, some loafers and wear a pork pie.