// today - 7 days
// toString() is just to print it to the console all pretty
Date.parse("t - 7 d").toString("MM-dd-yyyy"); // outputs "12-06-2011"
Date.today().addDays(-7).toString("MM-dd-yyyy"); // outputs "12-06-2011"
Date.today().addWeeks(-1).toString("MM-dd-yyyy"); // outputs "12-06-2011"