Now's the time for giving (7,3)
'now's' is the definition.
(I've seen this before)
'the time for giving' is the wordplay.
'the time' becomes 'present' (present is a kind of time).
'for giving' becomes 'day' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
Can you help me to learn more?
(Other definitions for present day that I've seen before include "Christmas for materialists?", "twenty-fifth of December?", "occasion for lots of give and take?", "Current", "Contemporary".)