For anyone that mourning the death of slide rulers, dry your eyes because the OITP Copyright Slider is alive and on the market!
While the slider vaguely recalls the horrendous Mathland modules I suffered through in Department of Defense Dependents Schools, it does indeed seem like a useful tool for establishing the year in which copyrighted works (in the US) enter the public domain.
I personally am often befuddled by all these term extensions and multiple international harmonization treaties, so this copyright geek tool from the Office for Information Technology Policy might indeed be worth the $5 investment.
"This single, sturdy product provides instant access to copyright laws and guidelines. Simply align the arrows by date of publication and determine a work’s copyright status and term. And the “Permission Needed?” box provides a quick answer to this very important question."