There is one file that I always made changes to, but that I never want to be checked in. I would like TFS to block me from ever checking it in or committing the changes. H
Another option is using a custom check-in-policy. You can build your own or use Forbidden Patterns Policy from the TFS 2010 Power Tools. Of course you would need to be an TFS admin to install it and it might not be the thing you want in your situation. Also any check-in-policies can be overridden.