They have to live somewhere. Bikes of mine have been hung on walls, in closets, even under beds. Some riders are lucky enough to have sheds dedicated to their transportation. Here are a few ideas from Flickr...
Some bikes are lucky enough to live inside this door pictured above, from Greg_E's photo stream.
Bikes on a Wall from Stronglight's photo stream.
Also from Mike Grenville's stream.
Bike hanging Cunning Stunt's photo stream.
In the back of a truck from Urbanage's photo stream.
Bikes on a barge from Sybren A. Stüvel's photo stream.
First photo from Fulv's photostream.