#ifdef _DEBUG
    #define __REVIEW_ME      / ## / 
    #else
    #define __REVIEW_ME      $review_me$
    #endif

When reworking a large amount of code, this can be used to tag places that may need another pass or a review. The debug version will build fine, but the release won't until all review tags are removed.

This also allows adding free form comments if needed:

    foo += 13;    __REVIEW_ME -- why 13 ?!