Last week, we looked at an iPhone ad from Amnesty International that turned the device's "Slide to Unlock" feature into a symbolic act of political protest. Here's another ad that toys around with that feature—this one a bit more playful. It's from Audi and AlmapBBDO in Brazil, and it reimagines "Click to Unlock" as a winding racetrack. For users who play along and circle the track, the ad opens an app for Audi's iPad magazine. Simple and clever. Via @luckthelady.