Grab a friend and come to play the new Magic: the Gathering set, Eldritch Moon.
Each team of 2 will have 8 packs of Eldritch Moon and 45 minutes (plus however much basic land is needed) to build two 40 card decks. Play pits each team against other teams in single games to determine who is the Two-Headed Giant-est.
Find more details about this format here. Note the above deck size limit is based on this being a sealed event and overrides the constructed rules.