Well, I kinda explained my nickname in my original siggy. As a lot of you know, I'm a groundskeeper by trade. In this part of the Ozarks, it's very rocky. In fact I go through several sets of mower blades each season.
One afternoon it was too hot to mow anymore that day, so I decided to go up to the shop and sharpen mower blades. One of the guys in the shop said he'd "heard me out there mowing rocks all morning."
When I got ready to log in to a new sight that night, it asked for a screen name and "Rockmower" just popped into my mind. I now use it on nearly all the sights I frequent.