I used to. I used to ride Newport around 7 hours a week when I lived there. Even living in London, I'd be there once a week, travelling 3 hrs each way on the coach (and Herne Hill at other times).
Now, with an olympic-standard track ten minutes down the road, I can't be arsed. Germans haven't got a bloody clue how to ride it... no coaches, and they really do just ride round and round and round... in fact, they seem to treat it as something you do when you can't ride on the road, rather than a separate discipline in itself.
Finding yourself in a string with a rider on the front who's determined to show everyone how big his balls are by staying on the front for 30 laps (of course, with his speed constantly dropping as he gets more and more tired) is not exactly conducive to leg speed or to riding fun...
I've tried explaining through-and-off, chain gang, train & station, Spitfires (heh.) etc., but they just look at me with blank incomprehension.
Still, to echo Dave, you really, really, really have to give it a go. To steal a phrase from Woody Allen: "It's the most fun you can have without laughing."