One of the most unique smartphone applications is the WalkIN app, which caused a lot of buzz at SXSW Interactive.
There are lots of restaurant apps to choose from, but the WalkIN app is one of the few that provides interaction between guests and hosts. This clever invention lets people reserve a table by simply scanning the QR code at the door. In other words, no more waiting in line or yelling at the host; you can simply walk away and grab a coffee knowing that you're on the list. On the restaurant side of things, hosts can monitor and manually add guests onto the list. They will then notify you when a table is ready.
The WalkIN app is a wonderful feature to have on the smarpthone on a Friday/Saturday night when there's a long queue at the restaurant. Developers are currently working on more features.