How do you create an array/collection in a workflow?

I just want to declare a simple array.

var x = new Array();

What I'm trying to do is send a daily report that lists each user and how many tasks they have open in each State.  Ideally, I'd have a 2 dimensional array to store the values before sending the email, something like

User[0] = Scott
User[0][0] = 6 //"open" state
User[0][1] = 4 //"in progress" state
User[1] = Steve
User[1,0] = 3 //"open" state
etc

Then once I was done looping through and building the arrays I would send the email.