<html><div style='background-color:'><A href="http://en.wikipedia.org/wiki/Critical_Mass#.22Corking.22">http://en.wikipedia.org/wiki/Critical_Mass#.22Corking.22</A><BR><BR>It's when cyclists block oncoming traffic, like when the light is going to change, to keep the mass from splitting.<BR>
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<P>365 Urban Species: Click the link for a different city creature each day!<A href="http://urbpan.livejournal.com/tag/365+urban+species">http://urbpan.livejournal.com/tag/365+urban+species</A> </P>
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