One of my favorite drinks in Singapore is Soursop.  As a juice, in a freeze, however it can be done.  I just like the taste.  The best shop that I know that specializes in this is Meilock Soursop at Old Airport Road.

The menu is all about Soursop.  It can be combined with everything and made into a juice/freeze.

One of my favorites is below, the Soursop Freeze with Sour Plum.  Such a cooling drink.

Try their Soursop drinks, they are outstanding.  And they have buy 5 get 1 free with a card that they provide to you.