Anxiety occupies Will and Jack, who dread they may have had sex together; and spousal jealousy afflicts Grace, who's concerned that Leo is having an affair while on his medical mission in Guatemala.

Mira Sorvino plays a tipsy fashion editor---and Leo's old flame---who has a dinner-party revelation: she once had sex with Will in a college dorm. The news vexes Grace, whose jealousy has an impact upon Leo.

Tennis play is anything but courtly for Grace, Karen and Leo; a visit with Will's melancholy mom tests Jack's fear of her. Martina Navratilova has a cameo.

James Earl Jones parodies himself as a student in Jack's acting class, where that famous deep voice takes on the timbre of a Lear on helium. Elsewhere, Will tires of his roomie mom, but dreads confronting her.

A gay spelling bee preoccupies Jack, who's coached by Karen; Grace's illness turns Will and Leo into a gallivanting odd couple, out on the town for high tea and a hockey game that has Will shrieking in fear.

Dylan McDermott plays Will's flirtation, who, like Will, is a caretaker for his mom; John Cleese portrays Karen's latest fling, the father of her sworn enemy, her late husband's lover.

Jack Black guests as a mirthful MD giving a physical to Karen, who submits only after the doc checks out Will. Laura Kightlinger has a cameo as the physician's sassy nurse. Also: Stephanie Faracy plays an administrator at a nursing school that enrolled flighty Jack

A marital crisis upsets Grace, who reluctantly confides in Will after leaving Leo in Cambodia; nursing school flusters Jack, intimidated by a no-nonsense instructor (Lea Delaria) who gets set straight by Karen.

Candice Bergen guest stars as herself, reveling in a silly one-upmanship battle with her old friend Karen at a fancy restaurant, where Grace is wooed by an affable loser (Tom Everett Scott) and Will is fancied by a comely bar patron.

A Barry Manilow concert enthuses Will, an avid fan not above coming on to a staffer with direct access to the star (playing himself in a cameo). Debbie Reynolds reappears as Grace's mom, engaged in a spat with her daughter.