Previous/Background

Sheldon and Leonard are roommates in an apartment in Pasadena, California. In the first episode, a mysterious female moves in across the hall. Leonard invites her over to lunch with Howard and Raj, which sparks a relationship with Leonard and a friendship among the guys.

Currently

(As of Season 7 Finale)

Penny finds Howard a girlfriend, and they eventually marry. Sheldon finds Amy Farrah Fowler on online dating after Leonard and Howard sign him up secretly. Raj finds Emily on online dating, and is able to talk to her after the Season 6 finale, when he talks to Penny sober. Leonard and Penny get engaged in the Season 7 finale.