JERSEY CITY—With Sunday's NFL title game being staged just outside New York City, football stars in town have partied and socialized at a Super Bowl level. Members of the Denver Broncos and Seattle Seahawks have indulged in West Village restaurants, Chelsea nightclubs and Knicks and Nets basketball games.

Broncos linebacker Nate Irving has his own plans for a wild week: He will stay in his Jersey City hotel room and, for three hours a night, try to capture adorable monsters with names like Pikachu and Jigglypuff in a Japanese...