Sounds like the one I bought from wal-mart. I actually bought 2 from wal-mart, one for $3 and one for $10. Neither worked. It would actually record steps while I was sitting at the desk typing.
I found one that works wonderfully... I borrowed it from my mother for a day, who is a public health doctor doing a study on exercise in Amish communities for her master's. Needless to say it is one of those pedometers that costs hundreds of bucks. Literally. :X It was incredibly accurate though.
I'm going to be doing some research on them, I've heard a lot about the Sportsline models, and my price range is under $40 including shipping, cuz I'm a cheap college kid.
But I am loking for something with a 95% accuracy rating minimum. I'll post the top brand name models if I locate them.