We done Homer and Marge Simpson last year which went down a blast
Simple to do as well

Just go buy yourself some yellow and brown face paint
A yellow Swimming cap
A couple of (Painted black)pipe clearners for the two strands of hair !!!
The eyes are the best bit
Cut a ping pong ball in half and attach it to some elastic and punch a couple of holes in the middle
For Homer, i just wore my jeans and a white shirt as the painted face and eyes done it for everyone
The mrs wore a 50's style dress we got from a charity shop for a fiver and some red beads
We done her hair by sticking two long ballons up a pair of tights and taping them together and then sticking loads of cotton wool balls to it and spaying it with blue hair paint which you can get from smithys along with the face paint
We came second by the way and it cost us next to nothing to do and was a real giggle being them for the eve as everyone thought we were them
Sorry i aint got any decent pics on this pc as we got a new one not long after and lost the scanner so i took a piccie of the "event pics" we have framed
Do it dude, you will have a blast
Oh and dont forget to get a drunken early morning shower to remove the paint or you will wake up in a yellow bed

Regards
Ian