Tim, it's always quite lonely here in the Digital Projection Forum
I've never profiled a projector, but I'm pretty sure you should set it on sRGB (unless AdobeRGB is an option), as that is the most color accurate selection on the projector. What I did recently to color test a projector was to view color reference test images in the sRGB color space. Here is a good source of test images:http://www.northlight-images.co.uk/article_pages/test_images.html
Most of these had to be converted to sRGB in Photoshop, as they were in AdobeRGB. I chose a colorimetric conversion, not perceptual, so that most, if not all, of the colors would remain unchanged. Luckily, our projector was spot on, so no adjustments had to be made.
You should leave the projector on sRGB all the time and all of your images should be converted to sRGB before viewing on the projector. [If you are running a color managed program such as Bridge/Lightroom/Photoshop on your laptop, remember to change the working color space to sRGB so that the images on the laptop screen also look color correct. Correction: I think that this is probably unnecessary as long as the photos have been assigned an sRGB profile]
I would love to hear from people who have actually calibrated and profiled a projector, what equipment they used, and what their experience was. I understand that is a difficult endeavor.