... Well, technically it's Pysc 157. 

This week Nerdette host Greta Johnsen speaks with the professor responsible for the most popular class in Yale University's 316-year history. Laurie Santos created a course called "Psychology and the Good Life” and about 1,200 students quickly enrolled in it. 

Put simply, the course teaches students how they can be happier.

“The good news is that we can do it,” Santos tells Greta. “The bad news is that like all good things in life, it takes a lot of work.”

First, listen in as Santos gives us three main recommendations (1. Socialize; 2. Prioritize time over money; and 3. Remember you're too blessed to be stressed). Then, take the course yourself! It's free online via Coursera.