For the most part, Cajamarca is a pretty quiet town, although it has at least two spots that make an evening out worthwhile.
Peña Usha Usha, at Amalia Puga 142 (tel. 076/997-4514), about 4 blocks from the Plaza de Armas, is a funky little peña bar with kerosene lamps, a smattering of tables and benches, a small altar, and graffiti everywhere. It's atmospheric and intimate, and Jamie Valera Bazán has been singing politically motivated songs here, either alone or with a couple of friends, for years. The bar, which serves simple mixed drinks only, opens at 9pm and doesn't close its doors sometimes until 6am.
The most upscale disco in town is Los Frailones, Av. Perú 701 (tel. 076/364-113; at Cruz de la Piedra, at the base of Santa Apolonia hill). The cover charge is S/15 ($4.95/£2.55) for men and S/10 ($3.30/£1.70) for women. A slew of bars and clubs attracting nightclubs is clustered along José Galvez between Amalia Puga and Amazonas, including Orni, Bambolé, and Indio Bar.
