2012 SUMMER OLYMPICS
NBC, 9:00 a.m. ET
Weekends bring marquee events that NBC, the parent broadcaster for these games, actually can televise live. The action starts early, of course, and in a very familiar British venue: centre court at Wimbledon, where USA's Serena Williams and Russia's Maria Sharapova fight it out for the gold medal in women's singles tennis. And around 2:30 p.m. ET, Michael Phelps is scheduled to swim his final event of the 2012 Olympic Games — and perhaps his final Olympic swim ever — in the 4x100-m. relay. And that's just for starters…