Not really a hack, but...
I've got a 1999 G3 PowerBook (Lombard) with the DVD package. I'd noticed that, when closed, the DVD drive's faceplate was never flush with the rest of the computer's case, and that lately it would rattle horribly during use. I opened the thing up and found a metal tab, that engaged a sprung clip that holds the drive shut. I bent the metal tab slightly towards the back of the drive with a pair of needle nose pliars, and the drive now sits flush with the case when closed, and is rattle free.