TheMadScientist - 2:22 am on May 11, 2010 (gmt 0)

I actually just looked at it for a minute thinking I should be able to come up with a starting point, but they do not have a 'THE_REQUEST' equivalent that I saw, so you could get most of them by checking for the QUERY_STRING string server variable containing a single character and then redirecting, and while this would solve MOST of the issue it would most likely miss: http://example.com/? because the query string is empty.

I would probably go with checking for the query string containing a character and then using a canonical link relationship to specify the version without the ? as the correct version of the page. It would look like this in Apache:

RewriteCond %{QUERY_STRING} .
RewriteRule .? http://example.com%{REQUEST_URI}? [R=301,L]

In ISAPI the best I can guess at is:
RewriteCond Query-String: .
RewriteRule (.*) http://example.com/$1? [RP,L]