tedster - 9:03 pm on May 10, 2012 (gmt 0)
This is the kind of thing that can drive us crazy. By any chance does your site have a site search function - or any other kind of form input for user navigation? If so, googlebot often starts trying some very obscure submissions in an attempt to discover what's going on.
Essentially in these cases, Google is trying to find "deep" content than normally doesn't see the light of day.