I am based in HK. not gonna be much nightlife on a weds night (as compared to weekend), but plenty of good eats in town. You could catch the last few horse races in happy valley weds night (i think the last race starts at 11pm or so), head to central and grab a drink at Sevva for the great view (expensive, dress code and closes at 12am). If you are still thirsty after that, you could hit up Captain's bar at the mandarin Oriental (for jet set) or head to wan chai bar district for more casual setting. They also have the red light district if you are into that sort of thing (just be mindful of your passport/wallet). Wanchai should have some late night food options on the street as well. If you want yum cha/dim sum on a thursday morning and cant speak chinese, you are better off sticking to a fancier place with an english menu. Victoria seafood in citic tower (admiralty) is a good but pricier option, or you can do the touristy spot in central at luk yu tea house (iconic), but honestly, you arent getting the real experience unless you find a local to take you.
For lunch, take a ferry from central pier to lamma island (sok Kwu Wan) find a suitable seafood restaurant (rainbow seafood is fine) and gorge yourself on crab, garlic prawn, scallop in vermicelli, fried mantis prawn, clam with black bean sauce, some cold beer and whatever else fits your fancy. The seafood is all selected live, and just let the waitstaff guide you in choosing cooking styles.
If you find yourself back at the airport with time to spare, head over to the foodcourt near gate 40 and indulge yourself at Cavier house & prunier for some balik salmon and a carafe of wine for a pre flight meal. It sure beats the hell out of shitty plane food.
