You can see them in the touristy areas of any large city like New York, Chicago, or Boston: young men performing for spare change by drumming on improvised instruments scrounged from dumpsters and building sites, like those five-gallon white plastic paint buckets. A street-level phenomenon since at least the early '90s (there was a popular jeans commercial featuring them during that decade, and one drummer made an appearance in one of Mariah Carey's videos), street drummers are a cool, improvisatory exhibition of creativity from unexpected sources. Perfect to be capitalized up...