It's the weekend -- and have we ever got some great apps to help you fill up the next two days!

From nuclear bunkers to photo-editing suites, and Apple Music playlist importers to run-and-gun actioners, check out our picks for the week's most newsworthy apps. You won't regret it!

“This awesome app proves the iPad is the future of education.” That’s what Cult of Mac’s Luke Dormehl had to say about Earth Primer earlier this week, and it’s hard to argue.

Apple made a big push to get school textbooks on the iPad a couple years ago, but adoption has been slow. Earth Primer, an interactive exploration of earth science that’s sure to make your kid’s jaw drop, sets the bar high for the sad state of the e-textbook market. Buy it for your kids or just to enjoy on your own.

Available on: iPad

Price: $9.99

Download: App Store

You’ve probably heard of FiftyThree’s Paper drawing app by now. Known for its intuitive, ultra responsive drawing tools, Paper is one of the most successful iPad apps of all time.

Previously based on the freemium business model (free download with in-app purchases), FiftyThree did something crazy this week and made all of its drawing tools totally free. I guess 13 million downloads gives you some wiggle room to give back.

So the Sketch, Outline, Write, Color, and Mixer tools are now bundled in the free app instead of costing $0.99 each. That’s pretty cool.

Available on: iPad

Price: Free

Download: App Store

Want a little Leap Motion action without the extra hardware? ControlAir is nifty little Mac app released this week that lets you control media playback with hand gestures.

Sounds cool, right? Kinda. The main catch is that your Mac’s iSight camera has to be on at all times for it to recognize your hand motions, and it only works with iTunes, Spotify, Rdio, Netflix, QuickTime, and VLC out of the gate.

I tried using ControlAir with my MacBook Pro, and it was surprisingly responsive once I got it to pick up the gesture that initiates its controller interface. The main problem is that a) I don’t want my Mac’s camera on all the time and b) I had to position the display at an awkward viewing angle to frame my face correctly.

It’s a neat concept, but ControlAir needs some work before it’s anything to recommend to your mother. Still, if you’re interested in this kind of futuristic stuff, it’s worth checking out

Available on: Mac

Price: Free

Download: App Store

There’s a plethora of fitness tracking apps that can tell you how many steps you’ve taken and where you’ve been. Some apps, like Facebook’s Moves, let you geotag locations and break down different activities (running, biking, etc.).

Gross is for those who just want to see their basic activity for the day, and it’s got a refreshed design and Today widget to help. Walking, running, and “other” activity is broken down into a helpful activity graph for the day. It’s a nice, clean app that does its job well.

Available on: iPhone

Price: Free

Download: App Store

After several months of private beta testing, Detour is finally out in the App Store. Inside you’ll find seven high-quality audio tours of San Francisco based on different neighborhoods. Think of it like This American Life meets the audio guides you get at the zoo.

These tours are put together with care and expertise, and you can hear some previews on the app’s website.

More cities will be added as the app ramps up, with an Austin, TX tour slated to drop in time for the South by Southwest next month.

Available on: iPhone

Price: Free — $4.99 per tour or $20 for an unlimited annual subscription

Download: App Store

One of our favorite iOS games has come to the Mac. Space Age is from the same people behind great games like The Incident, and it’s fantastic.

Set in the “retro-futuristic sci-fi world of 1976,” the game follows “a small but determined band of intergalactic explorers who land on a seemingly uninhabited planet, Kepler-16.”

The throwback design and original musical score makes this one a real gem. Playing it on a giant Mac display hooked up to nice speakers is the way to go.

Available on: Mac

Price: $4.99

Download: App Store