It's a bit of a scam though as the wording of the act technically excludes professionals (lawyers, accountants, etc. - which is especially bizarre for lawyers as all gov't run offices like court services are closed) from receiving the day off, and most corporations are giving this day off to employees by removing a day that had been previously allocated under the personal days off that form part of peoples vacation days (i.e. someone may have had three weeks vacation + 3 'personal' days for the purpose of attending medical appointments or unforseen situations like looking after a child due to illness. With this holiday, that person would only have 2 'personal' days to work with during the year). Kind of a silly concept that dates back all those many years...to 2008 (or so).
Federal employees do NOT have today off.