When I went to live in the dorms I knew I'd have trouble storing multiple bikes in one room. I built a bike lift that lifts 1 or 2 bikes and holds them horizontally against the ceiling, completely out of the way (20 bucks worth of 2by4s, padding, and barn hinges). It clamps to door frames and can be raised and lowered with one hand. When lowered, bikes can be lifted off as if it was a car-trunk rack and when raised you can easily walk underneath your bikes (depending on ceiling height of course). Aside from head room, almost no space is lost. I don't have any pictures, sorry. For my everyday bike, I screwed a hook into a wall stud and hang it by the front tire. In this way I was able to keep 3 bikes in a small room that I shared with a room mate.
My current place is spacious enough that my bikes stay on the ground but I'm just now moving to a tiny (and cheap) efficiency so the bike lift is getting set up once more.