It's about time. The MUNI system in San Francisco could use a yarn-bomb seeing that it's in major need of disinfection. Ishknits recently hit the Blue Line in Philadelphia with a "yarn bomb," captured on StreetDept's Flickr site.

Wooster Collective reports that someone named Conrad wrote, "Earlier today I got a message from a certain Ishknits yarn bombing artist telling me that she was heading out this afternoon to bomb SEPTA’s Blue Line and invited me to tag along to photograph it all for this blog. Needless to say I hopped right on the El, and from 15th street to 69th street and then back to the Dolphin street stop, she installed 3 pieces on 3 different trains. And even while we started on a near empty train by the end it was the beginning of rush hour and the train was packed, all the people on each train we very excited about the work.”