Come As You Are Party! My daughter did this for her 11th birthday!  First, as an invitation, she phoned all her friends and told them that they had to come to the party dressed exactly as they were when she called them(my daughter had dressed up while phoning to honor the party); they weren't allowed to wash clothes, do their hair, change, put shoes or socks on (but if they weren't wearing anything they'd have to where a robe or something, of course).  Once at the party, they opened presents quickly so they could get on to other events.  First they ordered pizza, and I specifically asked them to notify the delivery boy that he had to act very shocked when he saw them, and he did a great job.  Next they had cake. The cake had a picture of a girl wearing a robe, with very messy hair, with very wide eyes and an open mouth.  The second they viewed it, they all burst out laughing.  Then my daughter gave out a trophy with the same picture as the cake on it (there is a little shop down the street from our house that makes trophies) to the funniest dressed person, who was only wearing an extra long towel.  And last but not least, the most embarrassing part. I took them out to the movies.