Ouro Preto's nightlife is shaped by the federal university and the famous repúblicas — student dormitories that occupy old colonial mansions and throw parties most weekends. The bars below Praça Tiradentes, around Rua Direita and Largo do Rosário, fill with students drinking cachaça and Brahma until late.
Cafés open early for the day-trippers — most around the main square. Try the local cachaça (Minas Gerais is one of Brazil's main producing regions) and ask for it neat rather than in a caipirinha; the better small-batch brands are too good to bury in sugar and lime.