I'm working on the iPad app, and I need to show a menu with about 15 menu items. For the website I would simply create a menu with sub-menus, but for the mobile app it seems it is not the commonly used solution. Are there any common patterns to solve this problem? Are there any good apps that I can use as examples? I can only think about LinkedIn for iPad with a scrolling menu.
A nice format for displaying a large volume of menu items is the "Hamburger Menu". There was a question on this a while ago, with some nice screenshots which you can find here. As you can see it can be almost full screen (with a small sliver of main content as affordance on how to exit the menu) on a phone sized device, but doesn't need to take up the entire screen for tablets.
With 15 menu items, you also need to think "Do I display them side by side, or do I hide them under categories?".
It's better to avoid any kind of scrolling in a menu, so you could just display categories in your menu, and have each category slide open accordian style.