The paper presents the case study of BERLIN_LOKAL_ZEIT, a collaborative archive and exhibition project aiming to document and reflect individual experiences of the COVID-19 lockdowns in Berlin, Germany. What began as an observational effort in spring 2020became a year-long archive, exhibition, and broadcasting platform that generated various hyper-local interfaces. The paper articulates an improvisational approach to media architecture in the form of self-reflection by the project initiators. Necessitated by the limitations imposed by the lockdowns on cultural production and public discourse, the paper presents an alternative conceptual approach to media architecture that is not based on a fully-specified technological infrastructure for discourse and interaction but instead on improvisational practices that manifest themselves in different technical interfaces. This improvisational approach is not merely a mode of production, but raises questions of about the discourse of media architecture and its underlying assumptions of methodological rigor. In traditional HCI, systems and artifacts are often presented as stable and fully specified, while their users are considered interchangeable. In contrast, we consider urban media interfaces as improvisation-driven infrastructures (or improstructures) in which the actors and their relationships are stable, while the technologies they create are provisional and in flux. As a consequence, the defining property of media architecture is no longer the structural integration of media into architecture but the embodiment of mediated communication in objects and performances at concrete places. In an environment where many physical spaces are longer accessible and human contact among strangers diminished, the project explores the restorative function and capacities of media architecture for shared reflection and discourse in physical public space.