Work is the process of creating value. Don't mistake sitting at a computer for working. Some of your best work can (and should!) happen with no internet connection at all.
Even more importantly, working without a computer can (and should!) happen during normal business hours. Don't feel trapped at a computer because your boss expects you to be connected. Let the results of your improved performance speak for the themselves.
Walk. There are only a handful of tasks that actually count as work. Email and tweeting don't, but thinking does. And walking is proven to help you untangle difficult problems.
Draw. Sketching is another way to help you visualize ideas. You don't need to be an artist, you just need to be willing to put a poorly developed idea on paper. It feels weird to look at a bad idea, but once there, it's much easier to iterate on.
Talk. Creatives need to be able to hash out ideas. That's how a seed of a thought becomes a list of actionable tasks, then a project, then a product, service or business. Brainstorming sessions with friends and coworkers is a great way to do this. Add beer for enhanced results.
Sleep. Peak creativity happens when your mind and body are energized. Instead of squeezing more hours into the day, consider squeezing in more rest. It can make both your peaks and valleys higher. (Some companies will even pay you to sleep more.)
Read. Long-form magazine articles and books are near impossible to read on a computer. There's just too many pings and notifications. Time away from a backlit screen is a good chance to explore a topic in depth. And it helps you sleep.
Move. And not just on the treadmill. Learning and playing new sports is proven to be great for your body and your brain.