Gropes of wrath

A reader writes... Q: Here's a strange problem I've never run across. About three months ago, I started work in a small office where we're all crowded together and things are usually quite busy. One older guy seems to always be bumping into or brushing against me. At first I thought nothing of it, but after about the third time I got suspicious. I get along with everyone and don't want to mess up a good work enviornment. So I'm reluctant to tell him to stop it. But I don't think all these brushes are accidental and I want it to stop. Any suggestions?