Prisoners built two PCs from parts, hid them in ceiling, connected to the State's network and did cybershenanigans

And they would have got away with it too but for... Websense

We are impressed by five prisoners in the US who built two personal computers from parts, hid them behind a plywood board in the ceiling of a closet, and then connected those computers to the Ohio Department of Rehabilitation and Correction's (ODRC) network to engage in cybershenanigans."