This wonderful city/state has a wide variety of things to do and see. Have look on some of them.
Must to See:
Singapore Zoo/Night Safari
Jurong bird Park
Sentosa
Raffles Hotel
Old Supreme Court and City hall
Changi Chapel Museum
National Museum of Singapore
Must to Do:
Shopping at orchard road
Wind surfing at any of Sentosa Island beaches
Dance in nightlife options in Singapore River Area
Dining at Newton Food Center