Make no mistake about it, “Blue Collar TV” (7 p.m., WB) is a major departure for its network. Whether it represents a new direction or a sign of desperation remains to be seen.

A half-hour sketch-comedy series featuring the stand-up trio of Jeff Foxworthy, Bill Engvall and Larry the Cable Guy, “Blue Collar” has some impressive comedy credentials: the Blue Collar Comedy tour remains the second-highest-grossing stand-up act ever; the movie of the tour sold more than 2.5 million DVDs; and the “Blue Collar” TV specials have set ratings records on Comedy Central.

But the show is a bundle of contradictions. The “Blue Collar” tour was a stand-up smash, but this is a sketch show in which most of the sketches are flat, obvious, crude and invariably way too long.

• A zoologist travels shallow waters all over the globe in search of “Bull Shark: World’s Deadliest Shark” (7 p.m., Discovery).
• The series “True Spin” (10 p.m., VH1) offers the “real” stories behind pop tunes. Tonight’s show deconstructs The Go-Go’s “Our Lips are Sealed,” Poison’s “Something to Believe In” and other songs.

Tonight’s other highlights

• Another eviction on “Big Brother 5” (7 p.m., CBS).
• Eddie Murphy stars in the 2000 comedy sequel “Nutty Professor II: The Klumps” (7 p.m., Fox).
• Jay Mohr hosts “Last Comic Standing” (8 p.m., NBC).
• Death rides a roller coaster on “CSI” (8 p.m., CBS).

Late night

Natalie Portman visits “Late Show with David Letterman” (10:35 p.m., CBS) … Jay Leno welcomes Michael Moore on “The Tonight Show” (10:35 p.m., NBC). … Brad Pitt and Janet Jackson chat on “Late Night with Conan O’Brien” (11:35 p.m., NBC)