Summer lattes must be iced, but spending the time to start up the espresso machine to brew espresso for a single latte takes longer than I would like. My little iced latte secret: brew for the week on the weekend. On Saturday or Sunday, I run 8-10 shots of espresso. I store it in the fridge in one of those shake-up salad dressing containers (you can get one on Amazon for about $5, though any container would work - I just happened to have one of these).
Ready for a latte? Pour some espresso and milk into a glass, travel container, etc (1/3 espresso to 2/3 milk). Add some ice. Like flavors? Try adding some Hershey's syrup for a mocha. Grab some caramel sundae syrup for a caramel latte (forget the crazy expense syrups they sell at specialty stores and Starbucks - this stuff is just as good and less then half the price). This method to my madness keeps me well caffeinated, saves me money, and prevents the temptation of just getting that one donut or pastry with your coffee!