Over the past decade, a diverse community of biologists, artists, engineers and hobbyists has emerged to pursue biology projects outside of traditional laboratories. Though still in its nascent form, this DIYbio (Do It Yourself Biology) movement has given rise to a host of technical innovations and sharing mechanisms that enable hobbyists to experiment with organic materials. As these developments continue to expand science practice beyond professional settings and into hackspaces, art studios and private homes, HCI research is presented with a range of new opportunities and concerns. Our workshop will bring together a diverse group of designers and HCI researchers, as well as biologists, bioartists, and members of the DIYbio community to critically re-envision the role HCI might play at the intersection of biology, computation and DIY. This action-based one-day workshop will engage directly with DIYbio initiatives in the UK to explore the materials, practices and challenges of 'garage biology'. Drawing on presentations from DIYbio participants who work with organic materials, hands-on biology activities (such as extracting DNA), and structured discussions, we hope to address themes such as: opportunities and implications for integrating organic materials into interactive systems; technologies that support and hinder public engagement with science; and HCI's role in the public discourse around bioethics and biosafety.