One of my ex-gfs father was an avid biker. He biked from home to work (and back) 10 of the 12 months - and up in Canada, that's quite the feat. Anyways, the times that he finally brought his bike indoors, he hooked it up to this (as described by JS & Kaos):
www.velotique.com
That one is listed at $400, but there are others that just hold the back tire up off the ground for much cheaper.