Not in the way one might expect. (Skip to the 51 second mark in this video if you want the good stuff).
As in so many other cities today, OWS-allied movements took over various bridges, including the La Salle Street Bridge over the main branch of the Chicago River. The CPD, more known for busting heads and not bothering to take names than for delicate handling of anything, politely let the protesters occupy the bridge for a while. Then they talked to each protester, who agreed to get up and be cuffed and go away for an I-bond. No pepper spraying of 80+ year old women, no busting up of libraries. Let free speech happen. Whether this is the best strategy for the OWS protests to make some political headway, I'm ambivalent. Like Neil Steinberg and others, I agree that the OWS movement needs to register voters and elect people (even sellouts like Obama or other DINOs—who are indeed the lesser of two evils, but let's remember how much greater the greater of two evils can be). But I'd also say that anything which gets the local news to cover you and quote people making your talking points is a good thing for convincing the swing voters. Just let those voters drive home in a timely way. Which is to say, don't let Critical Mass take over this second phase of OWS.