Design News has published an interesitng on-line article
Gadget Freak Case #128: Syncing Music and Fireworks on how Deane Williams fixed up his PC to synchronize fireworks with music. He used his PC’s parallel printer port to connect the circuit controlling the fireworks. The software was written in Agilent VEE 8.0 but Williams says it could have been written easily in Visual Basic 6 or any similar language that can use ActiveX calls. There is a video available how it work. More details including circuit diagrams is available in Word document format.