This paper is an ethnographic and theoretical study of the Shia mourning rituals of Muharram performed during Ashura (27, December) of 2009 in Tehran. The 2009 Ashura ceremonies, performed months after the disputed presidential elections when Iran’s major cities erupted in the most intense street demonstrations, represent an example of politicized Muharram ceremonies, commemorative rituals performed for the martyrdom of the Prophet’s beloved grandson, Husayn, in 680 C.E. The paper, however, argues that the political dimension of 2009 Ashura demonstrations emerged not as a manifestation of formalized politics, but carnivalesque theatricality with a cluster of significances, manifesting dissent through various masquerade practices that mark a breakdown lived spaces and ultimately reconfigure urban space-- however temporary. The centrality of the city space in this study is highlighted with the unfolding of 2009 Ashura protests from the morning period, when the demonstrations began, to nighttime in distinct urban neighborhoods or collective sites, followed by a temporary collapse of order through symbols and performances of mourning mixed with laughter and jest. The first part of the paper is an exploration of the Ashura carnivalesque that correlates with a theoretical consideration of the politics of carnival demonstrations, somewhat followed by Mikhail Bakhtin in Rabelais and his World, but also providing an ethnography of distinct carnivalesque practices such as cursing, misrule, vulgar slogans, and grotesque behaviors through which mourning becomes a form of political humor performed on the street level. In the second part, the study argues that politicized Ashura canrivalesque should be contextualized within non-political Ashura canrivalesque ceremonies concurrently performed around the urban areas where street demonstrations take place. While in the first part the temporal dimension is emphasized, the second part considers the spatial framework through which political rituals become meaningful in an urban context. The final part of the paper critically reconsiders the concept of “Karbala paradigm” and argues for an alternative conception of Shia mourning rituals--at least in its Iranian manifestation-- and, more importantly, politicized ritual action.