How do I get the system date and time and store in a variable

How do I get the system date and time and store in a variable

I want to store the current date and time in a variable using C#. How
would I do that if it has to be in the format YYYY, MM, DD, HH, MM, SS?
I.e. I know I can store midnight on January 1st, 2013 as;
var time= new DateTime(2013, 1, 1, 0, 0, 0);
How do I do this with the system date and time?