On April 1 of this year, the Golden State Warriors were 37-0 at Oracle Arena. That same day, the San Antonio Spurs were also 38-0 at the AT&T Center (they got to 39-0 the next evening). After winning their first 75 home games combined, the two squads were just sevens victories away from putting together simultaneous undefeated seasons in their own buildings.
Of course the Celtics ruined the Warriors perfect home campaign that night (the biggest regular-season win in the NBA this year?