Ruin the party.
tired of parents that have people over and pretend you weren't born?
not allowed to touch the 'good' towels or even leave your room while the company is over?
stressed from the day of endless cleaning and manic need for picture-perfect rooms?
it's time to ruin the fun... or at least get them a bit more stressed...

dress up and stand in the corner of the room ... tell the guests you're a mannequin

put up a 'you are here' map in the hallway

ask if you should dress up and sit in a corner pretending to read a book in case guests stumble in your room accidentally while looking for a bathroom

change your tag to 'unruly daughter/son'

walk around in your underwear

get confetti and 'celebrate' in the living room

draw a bad picture and then show it to them all saying how your teacher says your special

wander in and say 'have you seen my condoms?'

as the guests are arriving, tell your parents the toilet is clogged up and there is shit everywhere

wander in wearing underwear, socks and a shirt... proudly announce that you're a big girl/boy now so you don't need diapers

pour some water on the carpet in the corner... when asked what it's from look embarrassed and say 'i just couldn't make it in time'

ask for all the guests autograph in your book of 'people that my parents love more then me' book

leave a trail of sparkles all over the house

throw all the guests coats on the floor and encourage pets to sleep on them, if you have no pets then you sleep on them

soak all the towels in the bathroom in warm water, wring them out and hang them back up nicely

rig the soap dispenser to come apart or splurt someone with the soap

leave a pubic hair on the toilet seat... replace each time it's removed

hide something stinky in the bathroom

put what looks like (or is) a used condom in the toilet along with some red food dye drops

put garlic power on any chips out for the guests

walk in "oh don't mind me, i'm the child she never had" so your mother can tell stories about how she is barren and missed out on having kids

tell them how you're the adopted kid that was rescued from the dumpsters and that you only have to work 20 hours every day to show them how much you appreciate them saving you... and how much fun it is when you play 'magic show' and they make you disappear for a few days into the closet

grease up the soaps with vegetable oil (maybe the taps/faucets too)

sprinkle sugar on the butter (so it's crunchy)

put a tag that says 'daughter' or 'son' on you so the guests know what you are... label other things accordingly

go into the closet and pretend like you've been locked in there for a day or two... moan for food

if it's cold outside... dampen the soles of the guests shoes and put outside until just before they go to leave...

when made to help vacuum, leave horrendously noticeable vacuum marks on the carpet

if possible, interloc all the chair legs at the table so its next to impossible to pull out just one chair

sprinkle baby powder on the chair seats (if it's not noticable) so guests get white clouds on their asses

have a screaming 'episode' on the floor... be sure to get yourself bleeding onto the carpet

go into the bathroom and sleep in the tub

take the smelliest, nastiest shit in the 'guest' bathroom

hide all the toilet paper

'accidentally' drop a bag of flour on the kitchen floor and then 'accidentally' fall/step into it

if made to speak the the guests, answer with one word answers and keep glancing at your parents as if fearful of the 'wrong' answer... ask if you 'did ok' before they leave