Another good day trip is Lamma Island, 25 minute ferry ride from Hong Kong Central piers. If you're into some walking you can take the ferry to Sok Kwu Wan and hike 1-2 hours to Yung Shue Wan for the ferry back. No private cars on Lamma, it's a laid back and scenic side of HKG. Lots of cheap eats and drinks. Back in Central, Lan Kwai Fong is also worth a look for drinks and nightlife.