Mockup.io

I'm surprised they don't provide example mockups. Anyone know of any or have experience using this?

We provide sample project with the description of main features. To open it use “Create Project” button at the upper left corner, choose the device to prototype for and press “Create” button. There in your new project you may find “Try sample mockups” button. Then you may simply d&d your own mockups to the project. Most of the actions with the mockups are made via context menu (right mouse button click). For project or account administration use “Settings” button in the top right corner.