The year is ending, and a new one is starting. Get a good start for 2021:
Top up your SRS/CPF SA
Time required: probably 2 minutes if you already have an SRS account, and another 5 minutes if you need to apply for one.
Get dollar-for-dollar tax relief when you contribute to your Supplementary Retirement Scheme (SRS) account up to your contribution cap which is currently $15,300 for Singaporean/PR and $35,700 for foreigners. You have to do it before the end of 31st December 2020 to qualify for tax savings for this assessment year. DBS, the bank my SRS account is with, specifically states the cutoff timing to be 7PM on 31st December.
You may also top up your CPF Special Account to get dollar-for-dollar tax relief on up to $7,000, and it should be processed almost instantly if you use PayNow.
Do check your own eligibility for tax relief before proceeding.
Donate to a charity
...