Some phone apps aid us in practical ways, others help kill time, and then there are the varieties that encourage people to spend money. Leav does none of the above. Instead it invites people to experience cities in new ways. The free app, which launched earlier this year after a successful Kickstarter campaign, features unlockable elements that folks can enjoy via phone based on a user's location, time of day, weather, and other variables. For example, a short film might become available at an intersection when it's snowing, a song can be listened to at dusk in a park, or a photo series can be viewed when traveling on a certain day. Do a little exploring. Who knows what you'll find?