Notions of Expenditure is a "request for speculative proposals to re-design exercise equipment to generate and store energy; and/or to retrofit gyms to function as local power sources linked to the grid." Initiated by artist A. Laurie Palmer, who also initiated a project for DuSable Park in Chicago, the project is aided by the support from Gallery 400 at the University of Illinois at Chicago
Proposals can be uploaded directly from the web page, with submitted proposals available for viewing (two at the time of writing). The deadline is May 1.
Update 01.25.06: The above links have been fixed. As of this update, about twenty projects are featured on the web site.