Also, here is some mostly Free things to do:
https://www.changiairport.com/en/discover/attractions.html#/…
Enjoy a free 2-hour bicycle ride and explore the great outdoors from Changi Airport before your next flight out. The Changi Airport Connector cycling path links you to Singapore's park connector network. Explore outdoor gardens, the Changi Jurassic Mile attraction, nearby beaches along Singapore’s East Coast Park, historical sites at Changi Village, and even downtown Marina Bay!
Requirements
- You are a passenger with a layover at Changi Airport of at least 5.5 hours, but less than 24 hours. Your layover time also has to coincide with GoCycling @ Changi Airport Terminal 2's operating hours.
- Your checked-in baggage should be through-checked to your final destination.
- You can make a booking of one (1) bicycle up to five (5) bicycles per transaction, up to hundred and eighty (180) days prior to your intended rental date.
- Upon arrival at Changi Airport, you are required to clear immigration as GoCycling @ Changi Airport Terminal 2 is located in the Public area. Visitors are to ensure that they meet the requisit visa requirements for entering Singapore.
- Passport, boarding passes, a valid visa for entering Singapore, and your bicycle booking confirmation are required. Your eligibility to participate in the tour is subject to entry requirements stipulated by the Immigration and Checkpoints Authority of Singapore.
- If you have bulky or wheeled cabin baggage, it is advised to leave them at a Baggage Storage counter (fees apply) in the public area before renting the bicycles.
- There is a limit of 50 redemptions per day. Availability of slots is on a first-come, first-served basis.
- Transit passengers are only allowed to enter and exit Singapore once during their layover period, as per guidelines stipulated by the Immigration and Checkpoints Authority of Singapore.
Sounds like a great way to break up a long trip!