This first one is admittedly ancient (well, from 2006) but Liberian Alfred Sirleaf reportedly maintains a "blackboard blog" in the middle of Monrovia, posting news and updates using no electrical devices other than his cell phone.
He uses his cell phone as the major point of connection between him and the 10,000 (he says) that read his blackboard daily.
Not all Liberians who read his news are literate, so he makes use of symbols. Whether it's a UN or military helmet, a poster of a soccer player or a bottle of colored water to denote gas prices, he is determined to get the message out in any way that he can.
Meanwhile Brooklyn firm Studio Gelardi has devised a contraption, Contrail, that attaches to your bicycle, accepts chalk, and leaves a mark of your path:
Contrail is a tool for developing bicycle communities. As you ride, contrail leaves a faint chalk line behind your bike. The goal is to encourage a new cycle of biking participation by allowing the biking community to leave a unique mark on the road and to reclaim this crucial shared space.
via neatorama and josh spear