aniac goes back a long, long twisted ways, to some roleplaying and a dial-up BBS in HS.
The origional occation was a game of Twilight:2000 which I was gamemastering and wrote myself in to as a NPC, tweaked somewhat to the completely nutso just for giggles. I nicknamed myself "maniac" to name the unit the team was all in as "Maniac's Marauders", as some military units are wont to nickname themselves odd ways like that. Russell Bornshlegel (kaleja) was in the campaign, along with a whole bunch of PONA. The most memorable thing was nearly killing myself off numerous times, and the infamous string of "left leg" wounds due to hit location dice getting stuck on (7? I think).
For giggles, I started using that as my handle on the TREX BBS shortly thereafter (around mid-85?). TREX was a local social/sex oriented BBS in Los Altos populated by a wierd melange of teens through very perverse adults. When I got to UC Berkeley in 87, I was used to using it, so when I went out to pay for a VAX account (there was no UCB open access at the time) I chose "maniac" as the account name.
I've basically used it ever since anywhere that didn't require a real-name based login.
-george william herbert