Displaying Ordered List of Posts Based on Custom Fields

I’ve been trying to figure out how to display a set of posts (within a particular category) based on values in two different custom fields.

Basically, I’m working on a conference program — each program item is a post in a category called “program item” with custom fields for “day/time” and for “location.” I’m trying to construct a template that will run through all of these posts and order them based on the conference schedule in the proper time slot and location.

I’m trying to figure out how to do this with the fewest loops possible. I could do a loop for each variation of time slot/location, but that wouldn’t be much easier than just entering the whole thing by hand.

If anyone has got any advice or any similar examples you could point me to, that would be great.