http://www.designboom.com/architecture/h3t-architects-bike-sauna/

czech republic-based practice H3T architects (vitek simek, stepan rehor, matej velek) has created a  'bike sauna', a transportable sweat lodge pulled by a tandem bicycle. constructed out of
light and durable materials for maximum ease of use, the project serves as a new and unconventional 
social tool that interacts with its immediate site.