Having the Olympics be a net plus involves using at as an excuse to build infrastructure (rail lines, etc) that you want to build anyway, and housing and facilities that you can reuse or otherwise recycle afterwards. Also, too, don't let the IOC sue anyone who uses the word "olympics" without licensing it first.
Use it as an excuse to create stuff that will be useful when the games are gone. Now I don't have much faith in the ability of local authorities to actually manage it, but that's the way to do it.
