Why does my car speedometer go whackadoodle catywompis a couple of times each year?

Every so often my speedometer goes wacky as if it were loose from it's bearings. It will just go flipping all over the place as if being pulled by a magnet. This only happens once or twice a year. I always drive the speed limit so it has nothing to do with driving. It's a 1995 Ford Taurus SW.

Haha yeah!

You probably have an output shaft speed sensor slowly failing. Or a bad connection (or wiring issue). Most likely replacing that sensor will fix your problem.