Doom on a single PC was fun. But the same game on our network with all those broadcasts running through our net, which hosted a university's PCs. That was bad. And I started it several times until I noticed that "I" was the cause for network slowdown.
Best part was that a sysop entered the room and within a second knew that I was the problem and that I was playing doom. He just told me "if you wanna play games instead of studying than play doom 2. This does not broadcast"