Today on TV

Joan of Arcadia (7 p.m., Ch. 2): Joan finds out more about Stevie than she intended.

College volleyball (7 p.m., Ch. 11): Cal-Irvine at BYU

Bernie Mac (7 p.m., Ch. 13): Bernie is sued for being a negligent parent after a child is injured at Bryana's birthday party.

Star Trek: Enterprise (7 p.m., Ch. 24): There's actually an answer to why Klingons looked so human during Captain Kirk's time and not-so-human during other "Trek" incarnations.

What I Like About You (7 p.m., Ch. 30): Jennie Garth, who plays Val on this show, used to play Kelli on "Beverly Hills, 90210." Kelli once had a fling with Dylan, played by Luke Perry. Tonight, Perry guest stars on "What I Like" as a guy who once had a fling with Val.

NBA (7 p.m., FSN): Celtics at Jazz

JAG (8 p.m., Ch. 2): Whether this show returns next season or not, David James Elliot has announced he's jumping ship. So tonight Chris Beteem joins the cast as a new JAG, ready to step into Elliott's shoes should the show get picked up for an 11th season.

Third Watch (8 p.m., Ch. 5): A gang leader declares war on the police.

Jonny Zero (8 p.m., Ch. 13): Jonny is tricked into doing the mob's dirty work.

Reba (8 p.m., Ch. 30): Barbra Jean's new dog disappears.

Blue Collar TV (8:30 p.m., Ch. 30): "Brady Bunch" star Christopher Knight appears in a sketch about "Brady Trash."

Numb3rs (9 p.m., Ch. 2): Were a series of railroad accidents simply accidental?

Medical Investigation (9 p.m., Ch. 2): A deadly disease circulates on Capitol Hill.