First-timers to this red-lit den in Williamsburg are greeted by its owner, Baron, an energetic dreadlocked Dominican, who runs around taking photos of friends, both new and old, and eliciting sounds from odd instruments (or objects) strewn about. The five-month-old bar is his living room: comfortable old couches, music to move to, a wooden dancefloor begging to be worn out, and photos of his mom and grandmother watching over the place. There's even an enclosed alcove for smokers who don't want to throw on a coat and gloves every time they want a cig. But what makes this house party really stand out is the cocktail menuaa well-thought-out list with a Latin American twist. Sweet guava margaritas and well-muddled caipirinhas ($6 each) are among the offerings, but the real star is the bar's namesake drink, the mamajuana (a blend of herbs, spices, leaves, and Brugal rum; $5), which is considered to be an aphrodisiac and a natural form of Viagra in the Dominican Republic. After one of those, it is quite possible that even the most chill party guest will be going all night long.