This weekend’s big military sporting event comes Saturday in Philadelphia. But this weekend’s big military sports-entertainment event comes Sunday afternoon in Norfolk, Va., when World Wrestling Entertainment packs the Norfolk Scope Arena with thousands of active-duty service members and their families for its yearly “Tribute to the Troops” event. Planning to attend? Wondering what your kids have gotten you into? Here’s a quick primer: 1. Tickets still available. Early this week, sailors waited in line, sometimes up to 90 minutes, for free tickets to the event at various locations throughout the Hampton Roads area. Now, the only way to get…