I've done some very very bad things but i'm not sure if they would be welcomed on a public forum...

However some of the ones i can mention are...
Ripping up a whole streets letterboxes then putting them all back at differnent houses
Knocking on peoples front doors at night then pull the fuses out of their meterboxes
Putting oil on the road at stop signs that are on steep hills then hide in the bushes and watch as all the oldies smoke it up as they try get up the hill, (even got the old man smoking it up much to my amusement) Also use to be a treat down at the bottom carpark at scarbs and up the hill at north scarbs in the day. Hours of entertainment after a surf with all the bogans doing bog laps.
Many more but my memory lets me down.
Oh to be young and stupid again...