To be in a combined mental state of tired and wired.
I see my colleague in the elevator on the way to the meeting room. I ask him how he is doing. He says, "I have been up all night to prepare this presentation for the board. I've been working on it non-stop for three days. I've been drinking coffees like a bandit to stay awake. I'm so toasted. I'm so wired, too. Man. Hell, I''m twired.
Maybe you're up late at night into the early morning hours searching the internet for anything and everything Twilight related...Or maybe you can't stop watching your trusty Twi-DVD, either way, you're most likely Twired!