This article introduces a practice-centred inquiry method called an "ethno-experiment". The method is built on a social constructionist understanding of practice as a social performance rather than as an individual's act. Additionally, it draws on Garfinkel's early ethnomethodological work and Marshall's self-reflective inquiry to construct a method of inquiry that centres on practice development rather than knowledge output. Having described the conceptual forbears of ethno-experiments and discussed the significant aspects of the practice, the article then examines ethno-experiments using an account of a particular series of these experiments used in work with a major engineering company. Finally, issues of quality in practice and assessment are discussed before it is argued that ethno-experiments provide three benefits to practitioner-inquirers: an enriched dialogue between theory and practice; the robust testing and evaluation of emergent practice; and the development of a scholarship of practice. (Contains 2 notes.)