An increasing number of amateurs are currently building rudimentary laboratories in their garages, kitchens or cellars, in order to carry out experiments in molecular biology. This paper analyzes the spatiality and materiality of this "garage biology" (or "do-it-yourself biology"). Specific techniques and objects are necessary to transform a private house into a site where experiments can be conducted. This paper shows that affordability, availability, and, above all, mutability are essential factors. We observe objects that are transformed, donated, combined, replaced, imitated, bought second-hand, etc. Particularly noteworthy is the use of "creative workarounds" around objects (to transform them and combine them in new ways) and around institutions (to bypass the economic ties between universities and industry). Garage biologists use various communication devices-websites, blogs, open source tools, forums, videos-to exchange knowledge and objects and thus to overcome certain boundaries.