“Smallville” (8 p.m., The CW): In an explosive episode of “Smallville,” a

“Smallville” (8 p.m., The CW): In an explosive episode of “Smallville,” a grudge-holding toymaker is suspected of murderous mayhem. Yes, a toymaker. Just doesn’t seem right.

“30 Rock” (9:31 p.m., NBC): “Mad Men” star Jon Hamm drops in on “30 Rock.” He plays the handsome — and newly single — neighbor of Liz Lemon, who is determined to spark up a relationship. Something tells us that luckless Liz will blow this one big time.