Hypersleep — Health & Fitness — Free ($0.99 for additional sounds)
Developer Fixdit sees no reason why your nerd love should have to stop just because you’re unconscious. So now we have Hypersleep, a space-themed sleep aid that includes white-noise-ified versions of the engine noises of various science-fiction vehicles. You can nod off to the engine idle of the U.S.S. Enterprise-D or the background hum of the 10th Doctor’s TARDIS. Or some other equally dweeby drones.
And that’s where the Nerd Tax comes in: The default noise is free, but additional (read: recognizable) sounds cost $0.99 each. But I’m pretty sure that if the sound of Serenity’s engine will help you nod off, you’re willing to pay that dollar.