HBO Go (Free; iOS)
What it is: A way for HBO subscribers to watch premium content on their iPhones and iPads.
How it works: Log in through your cable subscription user name and password, and voila, top shows wherever you can get an Internet connection.
Why it's great: There are lots of ways to watch video on your iDevice, but the shows on HBO are a cut above.
Why you might hesitate: If you're not an HBO subscriber, you're out of luck.
Who it's for: Travelers who want their HBO on the go.
Hello-Hello World (free; iPad)
What it is: A way to learn language with help from Hello-Hello users the world over.
How it works: Use the app to connect to native speakers anywhere, anytime.
Why it's great: It's free, plus the conversational courses were developed in collaboration with the American Council on the Teaching of Foreign Languages, which is a respected association for language teachers and professionals.
Why you might hesitate: No reason to hesitate. Hello-Hello has been helping people learn since Hello-Hello Spanish debuted last year. If you use an Android, BlackBerry or an iPhone, you'll have to wait; Hello-Hello promises versions for your device.
Who it's for: Anyone who wants to learn a new language while making new friends.
Hemispheres (free; iOS)
What it is: The elegant in-flight magazine of United Airlines, ready for the iPad.
How it works: Download the free magazine and swipe through gorgeous, full-screen pictures accompanied by helpful, well-written travel articles.
Why it's great: You don't have to travel United to get the magazine.
Why you might hesitate: Navigating through the app — learning when to swipe up, double-tap or swipe down — can take a little while to adjust to, but once you do, you're golden.
Who it's for: Anyone who wants to travel vicariously.