I recently did a Vipassana meditation course here in Alberta, and I got a lot out of the experience. The course involves 10 days of almost non-stop meditation, in total silence. Their instructions of what to bring and how to prepare are pretty good, but there's still little things that I wish I had known/done before and during the course.
Before the course
You will want to camp out for course spots - they go fast! The slots for women appear to fill up before men much quicker, but in either case, find out when registration opens for the time that you want, and register that morning.
Don't leave any tasks hanging before the course - you'll inevitably think about them. The ones you'll want to tackle most are anything due for the first few weeks after the course.
Their packing list is fairly complete, but some additional items you may want to bring to add to your comfort is earplugs and a mask for sleeping, and a water bottle (a simple plastic one with a screw cap should be fine). As always, plan for the weather. Since you won't be exerting much energy during the course, in cooler climates you can get away with wearing shirts and pants more than once. See if there is a packing list specific to your site.
Practice sitting on the floor 1 hour a day - find a good position, and get used to it. Do this while you're watching TV or reading a book, and get used to the feeling. You'll still feel sore during the course, but less than if you're starting from zero like I did.
Listen to the discourses. This gives you a general feel for the course, although honestly, after meditating all day, you'll pick up parts that seemed minor when you listened beforehand.
When you schedule the time off at work, give yourself an extra day after you get out. Trust me, you'll want that day when you get back to readjust to the 'real world'.
There's a few little lifestyle changes that you can change beforehand to make the experience more pleasant. At least a couple of weeks before the course, phase out all caffeine (coffee and pop) so you can deal with the withdrawal on your own terms. And if at all possible, try to change your sleep schedule to going to bed at 9PM and waking up at 4AM.
If you've got a car, see if you can offer someone a ride to the course. The sites are usually located in the countryside, so it's a bit harder for students and city-dwellers to get out to them.
During the course
You'll want to have little strategies for getting through the day. Spend 5 minutes on the first two days just figuring out daily logistics and a routine. Since the daily schedule is fairly consistent, this will make it much easier to focus on meditating.
Even though you aren't moving much, you will get hit with exhaustion eventually. Get in all the extra sleep that you can during rest periods, even at the start.
At day 4, there are periods of meditation where you should not be changing your posture. So right from the start figure out what cushions/positions work best for you.
Every time you feel like throwing in the towel, tell yourself to make it to the discourse. I found that these always pumped me up after feeling deflated, and often questions I had about technique ended up being answered in them. Of course, there's also times where you can discuss with a teacher any clarifications of technique.
After the course
Congrats, you made it! You should feel a real sense of accomplishment, because you earned it.
Don't beat yourself up if you don't manage to meditate as much as you'd like after the course. Do what you can, and remember that every step you take along the path brings you one closer to the goal.
If you decide to jump on the vegetarian bandwagon, do some nutritional research first so that you don't end up living off potato chips and macaroni salad.