Destiny, an upcoming game by Bungie. We do know more will be revealed at GDC next month, but a new ARG on the Halo creator's website hints that more may be revealed even sooner. How soon? Possibly next Monday: A row of numbers splayed across the top counts down from seven, and clicking on the next descending number each day changes the displayed weekday.
After the first task, the ARG appears to require the efforts of multiple players to solve; the second puzzle spells out "alone will not be enough." So if you want to get in on unlocking the mysteries of the ARG, study the second puzzle's clue after the break and head over to Bungie to add your contributions to the mix.