My favorite of that era was simply the working-as-designed simplicity of sneaking the Hayes modem hangup sequence into various protocols: actual Hayes modems used +++ with a time-delay to send commands such as ATH0 (hangup) but everyone else skipped that time-delay in an attempt to avoid the patent so you could disconnect any modem-connected system if you could figure out how to get it to echo "+++ATH0". Some IP stacks (e.g. Windows 95) would simply send the received ICMP payload as the response so a simple `ping -p …` would do it but people found ways to cause similar problems with sendmail, FTP, etc.
Pop into some random channel, send "/ctcp #channel ping +++ATH0", and wait patiently... a moment or two later you would be rewarded with a flood of "signoff" messages as the users' TCP sessions to the IRC server timed out (by responding to the CTCP, they had, in effect, told their modems to hang up).
The goal, of course, was to get the highest "body count" possible from a single CTCP message.
Smurf attacks, the "ping of death", AOHell, the latest sendmail and wu-ftpd holes of the week, open proxies... the Internet was a very entertaining place for a bored teenager from the midwest back then.
Ah, yeah. Takes me back to my college years. I was a sophomore at the time and was running Win2k server release candidates. Had a new freshman brag about having WinME, which was on the 9x kernel. Went back to my room in the dorms amd alternately sent a ping of death. Ping of death would crash him, but a ping flood was a DoS. His computer would hang trying to handle all of the traffic. Rendered the network unusable on my end while I was doing it, but the PC was otherwise fine (i.e. I could play offline games). Proved my point, he was humbled and stopped bragging and I left him alone after my little demonstration.