Last week, the Boston Celtics and the Philadelphia 76ers squared off in a unique regular season matchup at London’s 02 Arena. The game was part of a growing trend among the major U.S. sports leagues to play games in other countries as a marketing tactic. Over the past several years, contests have been played in places such as Australia, Mexico, Puerto Rico, China and Japan.London has been perhaps the most popular of the international destinations with the NFL playing at least one game in the United Kingdom every year …