Man, mumbled a name that sounded just too "generic" -- "Don Smith" or something like that; I didn't bother to memorize. Claims to be some kind of "home building contractor" and offers a "free estimate for the next project you have in mind".
I didn't feel like stringing him along to find out what the actual scam is, but it sure smells like one.
It's a holiday! Don't these jerks ever take a day off?