Front projection for business application?

[Uniquely]

First let me say I know next to nothing about front projection. I work in a nursing home... and wanted to propose to our administrator that we install a projector and sound system in our large or small dining room. It would be used for movie nights for the residents, playing the Wii with residents, and continuing education for the staff.

Our large dining room is about 40' X 30' and our small dining room is about 15'X20' I think either room could be used for the desired purposes, but obviously the larger room could accomodate more people. A fixed screen would not be feasible, so it would have to be a drop down, or something portable that could be stored elsewhere and set up when needed. High def would be nice, but if it were cost prohibitive, it would not be neccessary. Cost is going to be the most important factor in convincing the administrator that it's a good thing to do.

Any suggestions on what kind of projector and screen would be the most cost effective in this situation? Also would it better better to go for the larger room or smaller room... IOW will throw lenght affect cost? And one more issue would be hook ups. The projector could remain mounted to the ceiling, but any components like the DVD player, Wii and PC would have to be locked up after use. How would one arrange for easy hook up of components?