Warning: full episode spoilers follow.

Like a lot of shows this week, The Big Bang Theory aired its last episode before the big season finale. There hasn't been a great deal of build-up towards any one, particular season-capping event. Certainly nothing like the lead-in to Wolowitz venturing into space in Season 5. "The Gorilla Dissolution" started out innocently enough, breaking the characters off into pairs and having them deal with their separate conflicts. But it eventually resulted in something much bigger, and something long-term fans have been waiting an awfully long time for. So in the end, it was a momentous way to set up the Season 7 finale.

Dr. Wheaton, what horror have you unleashed on the world?

"The Gorilla Dissolution" divided its time pretty evenly among three pairings - Howard and Bernadette, Leonard and Penny, and Sheldon and Raj. Only poor Amy was mostly left out of the fun, though she probably would have been a third wheel in any of these three conflicts. And thankfully, each plot threat seemed to receive the attention it needed. I do feel that the Wolowitzes are a bit overdue for a more in-depth storyline, but this wasn't really it. Theirs was the relative weak point of the episode, centering mainly on Howard's patented brand of mother-loathing we've come to know so well. It was fairly amusing to see Mrs. Wolowitz become the prototype for their eventual child. But on the whole, I was glad the writers didn't focus any more attention on this material than they did.It was more satisfying to see Sheldon and Raj go off on a little adventure. I've noted many times in the past how this season has been good about exploring the less familiar and traditional character relationships, and the Sheldon/Raj dynamic is always one that can use more attention. And this plot thread was interesting because it generally toned down the humor and relegated Sheldon to a supporting player. After some initial laughs (Sheldon's fear of "bridge of nose" herpes chief among them), it became a more serious conflict as Raj dealt with the discovery that Emily is dating another man. Another exotic, foreign man, no less.One would think Sheldon would be completely ill-equipped to guide Raj through his latest heartbreak. But maybe Professor Proton's parting wisdom from last week is still rubbing off on Sheldon. He offered some surprisingly sound advice in telling Raj that he needs to stop idealizing every woman he dates and deal with his lingering fear of being alone. At this point, Sheldon is in danger of becoming a well-adjusted person. It was almost a relief to see him shoo Raj out the door so he could stick to his rigid bedtime. Another thing Season 7 has been better about is using Sheldon a little more sparingly. This episode was a necessary shift from some of the more Sheldon-centric storylines of recent months.But the big developments this week came in the Leonard/Penny subplot. It was neat to see Penny on set and acting her heart out for Serial Ape-ist 2. And it was a welcome treat to see Wil Wheaton back so soon after giving Penny some vital career advice and then finagling his way into his own role in the slasher flick. Wheaton really does seem to have replaced Kevin Sussman's Stuart as the unofficial eighth member of the gang.Let's be honest. Knowing that this episode dealt with Penny losing her acting gig and having to reconsider her life choices made it pretty obvious where all of this was leading. And I was a little concerned with how her character arc would be handled this week. We've already seen Penny wrestle with the idea of giving up her dreams and retreating to Leonard as a sort of safety net. I didn't want to see that choice recycled here. It would have been a negative development for both characters. But the writers handled the journey from Penny's firing to her latest marriage proposal with grace. She didn't fail in her acting pursuits; she had the audacity to want to do her job well and show passion for something everyone else treated as stupid. That's a pretty significant step for her. And Leonard directly addressed the notion that he's her safety net in life. Calling Leonard "the bran muffin" of Penny's life is pretty apt.So it was yet another awkward, fumbling marriage proposal. But the writing and the acting sold the ordeal enough that I was willing to accept that this is finally the right time for Leonard and Penny to stop screwing around and move their relationship forward. The awkwardness of it all was endearing, but I was also glad Leonard was able to seal the deal with a ring and a more heartfelt proposal. The show has danced around this development for years. At least the payoff was worth it.So the big question now is what's next for Leonard and Penny's romance. Are they going to get married in the season finale? Probably not. I believe Chuck Lorre has directly confirmed that no marriages are taking place this season. It's an interesting new status quo for the relationship that has been at the heart of the series from episode 1. But knowing that The Big Bang Theory will be on the air for at least three more seasons, we can only hope that these two won't stagnate worse than ever.