So I've got a presentation on Wednesday and I was wondering if there's anywhere on campus from where I can borrow the adaptor to connect my mac to the projector?

You could buy one at titles and return it... an alternative is to borrow it from a professor owns a Macintosh. AVTEK or Campus events has one and might rent it, but just for a student presentation it might be silly.

*Your best bet is to port your presentation file to a format that can be read by a PC and just use somebody else's laptop in class, its a heck of a lot less hassle!*

I'm pretty sure that Innis has some available for rent. You obviously need your student card and I think you can only have it for like a couple of hours but its better than nothing. Double check on Monday or Tuesday though in case im wrong...