Nightlife in Mexico City is very diverse. You can find mariachi, dinner shows, concerts, performing arts, nightclubs and everything you can imagine. By comparison with other cities like New York and Paris, the cost of an entertainment in the Aztec city is relatively low.
If you want a combination of music, art, coffee, bars and people-watching then go to La Colonia Condesa or Roma. The streets of these neighborhoods become crowded when the sun sets and it offers you a relax environment. If you’re into dancing, then head to La Zona Rosa. This neighborhood is a must-visit site for all visitors because it hosts the best clubs in the city. It’s also a meeting point for members of the gay community and although there’s no gay bars and straight bars (like in other cities around the world), tolerance and respect are a must. If you want more upscale clubs and bars, then visit Polanco. Here you’ll find the most expensive drinks in the city and the largest community of foreigners.
If you’re into more Mexican stuff, the go to Plaza Garibaldi, where mariachis and tequila will make the best of you’re night.
Not too far from there is el Palacio de Bellas Artes, where you can enjoy opera, ballet, orchestra concerts, dance and exhibitions.
Just one last advice: Mexico City is very dangerous at night, so make sure you’re going with a group of friends, always ride cabs, and don’t bring jewelry or a lot of money with you.