"Eureka," 6 p.m., Sci Fi Channel. In last week's terrific season opener, Henry erased a memory from the mind of Sheriff Jack Carter. Now only Henry remembers the alternate timeline he created, then had to abandon. Life returns to sort of normal: Allison — whom Carter loves from afar — is taking over Global

Dynamics, the massive research hub. Her ex-husband Nathan Stark is on the way out. In the transfer of power, the computer must shut down for hours. And that, of course, is when something goes terribly wrong. Don't expect the bright humor of some "Eureka" episodes. Like the other episodes, however, this one has a smart script and well-drawn characters.

Of Note

"The Bill Engvall Show" debut, 6 p.m., TBS. As a stand-up comic Bill Engvall combines intelligence and a low-key style. In producing this situation comedy, however, he merely aims for standard-sitcom adequacy. Engvall and Nancy Travis play the parents of three central-casting kids. Tonight, one of them has suddenly been promoted from third-string to first-string quarterback; he's not really into the game, but his dad and the cheerleading team seem excited. Much of this reduces Engvall to a silly, cartoon version of a father. Still, there are some decent laughs along the way. During a low-laugh summer, this is almost worth trying.

"America's Got Talent," 7 p.m., NBC. After weeks of auditions and callbacks, the show finally has its final 20 acts. Tonight, the performances begin and viewers start making cuts.

"House," 8 p.m., Fox. In a fairly good episode, Dr. House is confined to clinic duty, where a rape victim insists on dealing with him. Meanwhile, a homeless man simply wants to accept his fatal illness.

"Shaq's Big Challenge," 8 p.m., ABC. The kids will get free tickets to see Shaquille O'Neal in a Miami Heat basketball game. Chef Tyler Florence arrives to give them some healthier habits.