My favorites, because I can do them together:

2. Get Dirty

Dirt may be the new Prozac. Working in soil raises your spirits, in part because you pick up cheerful germs while digging. University of Colorado researcher Christopher Lowry injected mice with dirt-dwelling Mycobacterium vaccae and found increased serotonin in the critters’ prefrontal cortex. Getting your own dose is as easy as taking a walk in the wilderness or planting something. You don’t need to wait until spring: even in the dead of winter you can sprout basil seeds in a pot on your sunniest windowsill.

4. Crank the Tunes

That emotional rush you feel when you listen to your favorite songs? It’s chemical. In 2011, neuroscientist Valorie Salimpoor and her colleagues at Montreal’s McGill University conducted a study demonstrating that hearing music causes the brain to pump out dopamine, a neurotransmitter associated with pleasure and anticipated reward. Music lovers in the study chose what to play—everything from classical to Led Zeppelin to techno—then the researchers used a combination of technologies to scan their brains while they kicked back and listened. The dopamine surge was greatest just before and during favorite parts of a song.

14. Keep Animal Friends Close

Dog, cat, lizard, pig—doesn't matter. A 2011 study published in theJournal of Personality and Social Psychology found no consistent differences between owners of different types of pets, only that having one makes us healthier and happier. The study also concluded that pet owners have greater self-esteem and tend to be less fearful. 

I love the line "dirt is the new Prozac".

Indian food is like Prozac too!12. Eat Happy Meals

What you ingest can have a huge impact on the level of neurotransmitters in your brain. Here are the top feel-good foods and active compounds that lift your spirits.

• Elk. Elk meat is rich in tryptophan, an amino acid that helps the body synthesize the happy neurotransmitter serotonin. Also packing high levels are spirulina, spinach, turkey, egg whites, black beans, split peas, pumpkin seeds, walnuts, cashews, and almonds.
• Greens. They’re rich in folate, a benevolent B vitamin that also aids in synthesizing serotonin and helps ward off cancer and the degenerative diseases associated with aging. Follow Popeye’s lead: amp up your intake of dark leafy vegetables like spinach and collard and turnip greens.
• Gamma-aminobutyric acid. Nothing we eat actually contains GABA, a neurotransmitter known as nature’s Valium for its calming effects, but certain foods contain its building block, the amino acid glutamine. Among them: pork, beef, sesame and sunflower seeds, oats, cabbage, spinach, and parsley.
• Indian food. Curcumin, a compound in turmeric, boosts production of serotonin. In a 2013 study at the Baylor Research Institute in Dallas, 500 milligrams of curcumin twice a day proved to be as effective an antidepressant as Prozac.
• Healthy fats. In particular, docosahexaenoic acid (DHA), the most abundant fatty acid in the brain and an important moderator of mood and mental health. A 2011 study of military personnel found that suicide risk was highest among those with the lowest DHA levels. Where to get it? Cold-water fish such as salmon, mackerel, sardines, and tuna, plus shrimp and other shellfish.

On that last point, that's why "fish is brain food".

I've never had elk meat.

I do find the curcumin in Indian food to be an interesting recommendation, too!