lucy24 - 12:17 am on Jul 13, 2011 (gmt 0)
"Commerce" doesn't have to mean you're in it for the money. It simply means you're identified by this name in some public way. Search the USPTO-- assuming you are in the US-- and you will find lots of nonprofit organizations with trademarked names. (I just checked a few at random that came to mind.)
You will need a lawyer to tell you what happens if someone tries to trademark a name that is already in use for a similar activity by someone else, or a conventional phrase like, ahem, "I like food". Or what happens if someone succeeds at something so beyond-the-pale ridiculous, no normal person would ever think of trying it, like trademarking the name of your state.