Take the self-guided tours of old town with its Our Lady of Guadalupe church, the Naval and Historical Museum (free admission) and Los Arcos, four striking arches and outdoor performance space. Check to see if any free concerts are scheduled.
Take advantage of the many happy hours. Some bars have two a day; the gay-friendly La Fiesta has one pretty much all day with 15-peso beers and daily specials. Look for chalk boards advertising specials. Stop by Bella Napoli for an authentic wood-fired pizza.
As midnight approaches, hit the gay clubs like old standy-by Paco's Ranch, which goes until dawn. CC Slaughters, another popular late-night spot, has no cover; others have free entry before midnight. Also check for flyers wit special offers.