The bars at the Barba Roja restaurant and the Hotel Sí Como No are good places to hang out and meet people in the evenings. For shooting pool, I head to the Billfish Sportbar & Grill at the Byblos Resort (on the main road btw. Quepos and the park entrance). For tapas and local bocas, try Salsipuedes (roughly midway along the road between Quepos and the National Park entrance), which translates as "get out if you can." If you want live music, Bambu Jam (along the road btw. Quepos and the park entrance) and Dos Locos (in the heart of downtown) are your best bets. In downtown Quepos, El Banco Bar, Mar y Blues, Sargento Garcia's, Wacky Wanda's, and the Fish Head Bar at El Gran Escape are all popular hangouts.
Night owls and dancing fools have several choices here, although the bulldozing of Mar y Sombra down by the beach has really hurt the scene. The live music at Bambu Jam is often salsa and merengue, perfect for dancing. For real late-night action, the local favorite appears to be the Arco Iris, which is located just before the bridge heading into town. Admission is usually around $3 (£1.50).
If you enjoy gaming tables, the Hotel Kamuk in Quepos and the Byblos Resort on the road to Manuel Antonio both have small casinos and will even foot your cab bill if you try your luck and lay down your money.
If you want to see a flick, check what's playing at Hotel Sí Como No's little theater, although you have to eat at the restaurant or spend a minimum at the bar to earn admission.