Okay I wanted to annoy my sis so this is a good one
1. Take your sister phone number 2.call her when she is sleeping like at 3:30 am 3.get a screaming noise on your iPod or on any other device 4.put the screaming noise on the phone u r calling from and don't forget to record that 5.act sleeping and don't act suspicious .
Well that's what I did to my sis it was funny! Try it .