9.01 The Matrimony Momentum
Leonard and Penny make it to Las Vegas and get married, while Amy breaks up with Sheldon when he pushes for a timeframe over their relationship break. A very drama heavy episode, with both canon couples facing tension in their pairings.
But of course it's the Sheldon and Penny scene that shines.
Sheldon brings Penny tea when he hears things are not going so well between her and Leonard.