"Met Con" = "metabolic conditioning".
(work & family safe link to part of our FAQ (*strongly* urge you to read the whole thing)):
Essentially, any workout where the objective is to do as much work as possible in the shortes time possible . . . today's workout ("Grace") is both a metcon and a strength-builder (many CF workouts are). Other examples are "Cindy", "Chelsea", and "Fran".
I'll guess you need this link, as well:
Metcon workouts should leave you gasping and wondering where all the oxygen went.