In class we've been talking about how design competitions bring out some of the wilder solutions. But the winning entries in "Designing the 21st Century Street" seemed to emphasize how realistic solutions that already exist (in some form) can be applied in a careful and coordinated manner to transform an existing street in New York City into something that is safer and more livable. A common theme was making the city streets work for as many users as possible, often resorting to different kinds of traffic calming devices to make the streets safer.
For example, while Rogers Marvel Architects used some of the same elements as other entrants (bike lane in the middle, better pedestrian connections, reaching out beyond the street, etc.) their Streets for Everyone! design employed paving patterns in ways that emphasized their design concept. "Shared Space" lives up to its name by altering the boundaries between sidewalks, bike lanes and car lanes to make the entire street space feel shared by all users.
If you want something wilder, you might have to look to Di Magazine's competition for a Beijing streetscape. You can only get a tiny peek at the results of the Sunset Junction Competition. And I don't see the entries, but you can check out the results of the Syracuse Connective Corridor process that began with a competition.
Who needs winners? If we can look past streetscapes, the Rising Waters competition posted ALL of their entrants online. So you can see the realistic, the visionary, the colorful and the wacky.
If all else fails, you should at least look over the ASLA Student Design Awards.