Best uses of a slide projector that I've seen, outside of an academic or technical setting, have been:
A few dozen images that were tailored to a very specific audience of friends/family, that were flipped through slowly while we all talked about it [and frequently wandered off course]
Set up as an art-wall at a party, with a projector rigged to randomly advance on its own every 4-8 minutes. [Fairly sure they made a custom controller for it, as it was based off the last button press or auto advance, rather than being locked into a timer or something.]
I think that the key to the impact was that the focus wasn't on the slideshow, but rather the focus was the conversations generated by the slides.