As the saying goes: work hard, but play harder. Activities in the city really begin to animate during late hours. Not only will you be able to visit historical landmarks in the evening (e.g. Central Post Office, Notre Dame Cathedral, Independence Palace, etc.), you'll drive by the city's harbor, and enjoy two authentic local dinners. Also, get get a glimpse of the city's red-light district. One of your dinner stops offers local BBQ.
For guests who wish to stop by the local night market to pick up some souvenirs, simply let your tour guide know and accommodations will be made to add it to your itinerary.