Locally, there haven't been too many in-the-wild yarn bombings. You'll see the occasional bike rack or street pole with a touch of colorful yarn, but nothing more ambitious. I could be wrong; if you know about larger projects I'd love to hear about them! Purely as an appreciator; I love looking sometimes, it's the voyeur in me.
However, Pittsburgh has an extremely large and exceptionally ambitious project that will completely cover the Andy Warhol Bridge. If memory serves, the project was launched the better part of a year ago by the Fiber Arts Guild of Pittsburgh. I made a point of stopping by the Knit the Bridge booth at Three Rivers Arts Festival this week. Kitty Spangler, who has been working with the group from the start, was at the booth with a couple volunteers. She tells me that most of the blanket sections are complete but that they are still looking to make the black framing sections that will serve as a unifying element in this crazy quilt of a project.
The project is very complex, with multiple neighborhood coordinators enlisting the help of residents in making the panels and representatives from the project on hand at most community gatherings and street fairs. The project's statement about knitting a bridge between Pittsburgh communities is very apt.
There are several ways that you can help support this project. Knit the Bridge recently launched an IndiGoGo campaign to support the project. The funds raised will go to support installation costs, which is no small feat. If you want to get involved in making the panels, there are several drop-in sessions every week where you can go. They'll even show you how to knit or crochet and the company is wonderful. Or you can make a panel while you watch The Newsroom, and drop them off.