When I was a kid, using AOL with all my friends, I spent a few hours in Soundforge editing a clip of me saying "worms" as close to the AOL tone as possible. I did it pretty convincingly and began distributing the "You've got worms!" notification everywhere I could.

Anyone under 100 will probably think this was really stupid, but it was amusing to me - and all the other silly hacks on windows and such.