When i was like 18/19, i hacked into an unused intranet server of my local ISP. The stuff was all my local ip addresses started with 202.123.X.X so all i had to do was to run a hostname scanner and scan all active ip addresses withing that range. I got many pings back. Most of them i run vulnerability scanners and one of them was running IIS 4 or 5 and was vulnerable to Directory traversal. So I was just lurking around on the server and found out that it was an intranet server, way back from 1998. They stored all kind of stuffs and on another subdomain, they were running a full server serving mobile customers. I spent days lurking around, dowloading logs, phone numbers, software manuals, and cleaning my logs after i logout. It was the good old days :)