Miraflores concentrates many places for having fun. You may want to start your night relaxing at the cinema: Larcomar Multicines, located at Larcomar Shopping Center is a good choice, and once the movie is over you have several options to have a drink.
The closest one is in Larcomar itself: Gotika, in fact this is a disco, but has a very good bar. Another option nearby is only two blocks away: The Corner Sport Bar and Grill, where you can enjoy most of the major worldwide sporting events live on TV; they have more than 20 TV screens and two well-stocked bars.
Nor very far from there you will find the Brazilian-themed bar Media Naranja, with Brazilian drinks and specialties; also, Murphy's Irish Pub, with English.speaking staff; and the Calle de las Pizzas, where you can not only eat Italian food but also also meet people.
Other good places to have a drink and meet people are Huaringas Bar, not exactly in Miraflores but right at the limit between Miraflores and Barranco, famous for its Pisco Sours; and La Sede, a gay-friendly spot that has become very popular even among straight people and local fashion personalities.
If you prefer food and a live music show, Sachún offers creole music, very good drinks and good food also.
And if you are in the mood of gambling, Golden Palace Casino Lung Fung, Atlantic Casino and Thunderbird Hotel & Fiesta Casino are excellent choices.
Centro Comercial Larcomar
Schell 130, at Psje. Porta
Just off Miraflores' main plaza
Avenida República de Panamá 3165