I'd love to do a number of things like this, but the first thing that comes to mind that I would change if my place was my own: I'd paint stripes in one of my bathrooms. Can you tell by my background that I'm loving stripes right now? I always love them actually... they're classic and add interest to a space without being too busy. Their consistent rhythm can create a sense of calm while increased contrast can produce a more up-beat and fun intensity in a space. I think they'd be just darling in a powder room or bathroom. (In my case there is no "powder room" in my apartment.)
If I was creating my striped bathroom, it would be a simple painting project due to my budget constraints (probably a sky blue and crisp white combo), but you could also create an awesome striped look with wallpaper or tile. Unfortunately it seems like a lot of work for something I'll have to paint over soon enough. So instead I'll just dream of stripes and share some examples of what I'm talking about. Love me some stripes!
This last one I took with my iPhone in the beautiful Ann Sacks showroom at the Laguna Design Center. Fun right? Are you loving stripes as much as I am? What would you love to change about your rental if you could? I'd love to hear your ideas.