or caffeine pills, and put sleeping pills in food you sell to people. or you could sit in the middle and tell people its time to take your medicine, when they give a response say it's a suppository and you might need there help...
you could also dress up like a creepy guy and single out the people you think will stay the longest walk up to them without saying anything just give them a message speaking in a really gay/sexy voice say "i noticed you were really teeeeeense" when they look back in disgust just smile happily and lick you lips...
EDIT: another one would be to dress like a preacher and set up a podium in the middle of the lounge preaching neo-nazi ideals and spitting at people a lot