On the right side of this Latin coffee shop are large picture windows adorned with neon beer signs; on the left is a counter that seats eight. In between are red and white tables and chairs set on a hardwood floor and filled with a mostly Cuban clientele who clearly enjoy the social atmosphere as much as the cleanly prepared, low-priced renditions of their favorite foods. At breakfast time people line up for their café cubano. For lunch a kinetic crew slices up a slew of sandwiches from medianoches to BLTs. Dinnertime: vaca frita smothered in sautéed onions; oxtails, available as the daily special Mondays and Saturdays; and churrasco, a juicy, charbroiled flank steak that at $9.95 is as expensive as things get. Main courses are accompanied with rice, black beans, and maduros (fried sweet bananas). Desserts are mostly puddings (rice and bread), as well as the traditional flan. Sergio's is open late on Fridays and Saturdays, and there really aren't many times of day when it isn't humming along to the song of a full, joyous house.