Difference(s):
A task can be done at any time before the due date (in the case that it has one) while an event must start and end at a specific time.
A task is actionable whereas an event may be actionable or not (e.g. Father's day: all day; World war 2: 1939-1945).
Similarit(ies):
Remarks:
Non actionable events may generate tasks (e.g. task - buy present; event - mum's birthday)