In-person, Online and Back Again -- A Tale of Three Hybrid Hackathons

Hybrid hackathons, which combine in-person and online participation, present unique challenges for organizers and participants. Although such events are increasingly conducted, research on them remains fragmented, with limited integration between hackathon studies and hybrid collaboration. Existing strategies for in-person or online-only events often fail to address the unique challenges of hybrid formats, such as managing communication across physical and virtual spaces. Our work addresses this gap by examining how hybrid hackathons function, analyzing how organizers structure these events and how participants navigate hybrid-specific challenges. Drawing on established theories of hybrid collaboration, we examine key dimensions - synchronicity, physical distribution, dynamic transitions, and technological infrastructure - that shape collaboration in hybrid events. Through an exploratory case study of three hackathon events, we analyze how these dimensions are implemented and their effects on participant experiences. Our findings reveal differing organizer considerations of the hybrid dimensions in the hackathon design, leading to distinct experiences for participants. Implementation styles - favoring in-person, online, or balanced participation - led to varied participant experiences, affecting access to resources, communication, and team coordination. Organizers in our study also relied on technology to bridge hybrid interactions, but overlooked critical aspects like time-zone management, dynamic transitions, and targeted support for hybrid teams. Additionally, participants in their teams responded to gaps in event scaffolding by adapting collaboration strategies, revealing gaps in organizers' preparedness for hybrid events. Learning from our findings, we offer practical recommendations when organizing hybrid hackathon events and recommendations to participants when attending them.