What we're watching and why: "Rome: How Titus Pullo Brought Down the Republic" airs at 9 p.m. on HBO HD. It's the second episode of the new series. If you missed the first episode, you can catch it at 8 p.m. Elsewhere, the Yankees play the Athletics at 8 p.m. on ESPN-HD.
Here are some other HDTV programs showing on selected networks today, all in Eastern time:
ABC: Desperate Housewives (10 p.m.)
CBS: U.S. Open (11 a.m.), Cold Case (8 p.m.), Along Came a Spider (9 p.m.)
NBC: NASCAR Prerace (7 p.m.), NASCAR Nextel Cup in Fontana, Calif. (8 p.m.)
Fox: Malcolm in the Middle (7 p.m.)
ESPN-HD: Baseball Tonight (7 p.m.), MLB: Yankees at Athletics (8 p.m.), SportsCenter (11 p.m.)