My veterinarian's child was responsible for taking down the local Mom and Pop ISP for a weekend back in ~2000.
The kid pulled a prank on one of his friends, convincing him that he'd gotten his hands on 'Chrono Cross' for the Dreamcast with a trick involving a VCR and some sleight of hand. He then gave his friend a FTP link to a ~600MB CD of /dev/random garbage, expecting him to spend a two days tying up the phone while downloading it and a week trying to get it to work and wasting many, many CD-R discs in the process.
The friend, however, went straight to IRC. "Someone got a hold of some Bleem! code! <link> == Chrono Cross, fully running, saw it in action myself!"
That was at 5pm on Friday night. In under an hour the FTP server fell over and took the network gateway, running on the same machine, with it.
Remember how I said they were a Mom and Pop? Well, Mom and Pop were on vacation until Monday.