guys -- thanks for the replies.
I am pretty sure my speakers aren't blown -- power ratings are adequate, no disortion and I havent turned them up excessively where it would cause any damage (yet).

So I took out my deck and rcas and rerouted everything, made sure all connections everywhere were good and nothing was pinching etc. It hasnt done it in about a week, so I hope it was just a matter of something pinching or pulling or grounding off in a weird place or something of that sort. I will let you know if it starts happening again. . .but very odd indeed. . .thanks for the help