Episode 218, "Sleeping Dogs Lie"

Clinic patient:
Chinese girl looking for birth control, and her sick mother

The connection:
With the girl's mom in the clinic, House faces the same sort of situation that he's in with the main patient's girlfriend: He knows something they should know, but does he tell?

Obviously the stakes with the girlfriend are much higher. If House tells her the woman she's about to save doesn't love her anymore, she might rescind on the liver transplant, thus killing his patient. On the flip side, if he tells the mom about the birth control, the girl will just be grounded for a few weeks.

Which is probably part of the reason he does tell the mom in the end. But why didn't he say anything the first time? He just gave the girl the prescription and sent her on her way. My guess is, like with the girlfriend, it was in the best interest of the patient. When the girl came back after accidentally giving her mom the birth control, House probably figured that if she's too dumb to mix up the pills, she shouldn't be having sex.

Etc.
It's refreshing to be reminded of how quick on the uptake House is. The girl just had to say one thing before he figured out her motives. Her lying attempt fits in nicely with the episode's overall theme of deception ... as does the revelation that House speaks Mandarin, which he cleverly hid by doing and saying nothing while the girl translated. At any rate, after learning in "Distractions" that House speaks Hindi (or at least is trying to), he's proving quite the linguist.

Ignorance is bliss -- Episode 215, "Clueless"

Clinic patient:
Mr. Lambert, who has herpes, and his wife, who is suspect

"You're pleased. You think you've proved every marriage is a mistake."

The Lamberts' story unfolds in four parts:
1) Mr. Lambert is told he has herpes. House suspects the wife and a surrogate Mr. Miyagi (may he rest in peace).
2) The wife disputes the accusation.
3) House finds out the wife has herpes.
4) House finds out the husband gave it to the wife.

During the first two, the Lamberts appear to be the opposite of "the Nymphos" (the main patient and his wife) -- The Lamberts: bad marriage; the Nymphos: good marriage. Come the third time, when the Lamberts' plot thickens and nothing is as it seems, House starts to question the greatness of the Nymphos' marriage. By the fourth, it's clear the Nymphos' marriage is just as bad -- even if they were having more sex than the Lamberts. Guess that's not such a good gauge.

The Lamberts' last two appearances (seen and unseen) are also interesting in that they are a slight variant in the clinic-patient-solving-main-case theme. Normally, clinic patients give House one revelation -- the Lamberts give him two. When he finds out Mrs. Lambert has herpes, he bats around the idea that maybe she gave it to her husband in order to switch the blame. That led House to suspect some sort of foul play with Mrs. Nympho -- he just doesn't know the specifics yet. He figures that out in the Lamberts' last scene, when he tricks Mr. Lambert into giving himself away and after Mrs. Lambert tosses her gold ring to the floor -- the ultimate symbol of marriage discarded.

That symbol was also briefly shown in the teaser, when we find out the "sexual assault" is just a role-playing game for the Nymphos. It's fitting that the ring -- like their marriage -- is not as it seems.