go back to the end of 8th grade and i was in the same situation as you. living with my moms boyfriend and his daughter. what a nightmare.

i went for the toothbrush in the toilet thing plenty of times, sometimes i would just give the bowl a nice scrubbing with it. but it really isnt satisfying since they never really know about it.
one of my favorites was fucking with her computer, i would just go in there and burn parts of the computer with a lighter, her internet antennae mostly. pissed her off, she spent loads on new antennaes and thought it was shorting out or something the whole time. sometimes i would just go on her comp while she was gone and delete random files. once that included her AIM buddy list.
sometimes i would get her shoes, and go squash them in a fat pile of dog shit and put them back. she just assumed that she had stepped on it earlier and didnt notice. i tried to be careful not to do this stuff to frequently though so she did end up getting suspicious and accusing me a couple times.
one night i went out in the middle of the night and egged the shit out of my step dads car with about 20 eggs. and a neighbors garage with a couple eggs(so my stepdad didnt get suspicious), than went back inside and back to bed.
oo god the list goes on.
everyday my step dad came from home work all he would do is watch tv, so i would constantly break the remotes, i would just bang them against a wall until i could hear all the parts inside jinglin. that pissed him off a loooot.

of course i took my hits as well, im almost 100% sure that mystep sister was responsible for breaking my ipod. water damage and i NEVER got water on it while it was with me. and that was right at the time she suspected me of doing the dog shit shoes thing.

i was a vindictive evil little bastard, and looking back on all the stuff i used to do, i cant believe my life was so bent on revenge and anger.

in the end both our tempers subsided and it kinda just turned into this awkward we live in the same house but i havent talked to you in 6 months thing. thank god im out of that hell hole.

dude tell your dad to dump that bloodsucking whore

and sorry bout your bong man, it blows