One theory I've heard about sticking to a goal is to tell as many people about it so you can't back out. I'm now at that point with my 48 miles in 48 hours challenge. I've talked with people at law school and some other friends and bloggers. If they won't run the whole thing, they'll at least run a segment with me.
At this point, I'm planning to run 6 8-mile segments over 2 days in a yet to be determined weekend in October (based on company and midterm schedule).
I created a web site for this challenge to keep you posted on all the goings on. It's appropriately titled 48milesin48hours.com. Nothing like a domain name that just says what it is. At this point, it only has two entries but will grow as more information becomes available.
I've started to post on the site to keep visitors updated and I'm starting a Facebook group (oh my!), so if you're on Facebook and interested in it, let me know and I'll "friend you".
Of course, I'll continue to keep this site up to date with general training, mileage and progress as I always have.