I didn't get this last time around, so I'm glad they're doing it again! Coastal Contacts is offering 10,000 Facebook fans (who haven't previously gotten a pair of glasses from them for free) a free pair of glasses. You can read about it here. The code you'll need is displayed once you become a fan. The glasses will be free, but you'll need to pay for shipping charges.
What I would do is this:
1. Go to their site and pick out which ones you want. Book mark the page.
2. Dig out your prescription (you'll need a valid one).
3. Make sure you have all the info you need (PD - pupillary distance - is nice to have.)
4. Have a back up pair that you'd want if your first choice sells out.
5. Be on and ordering at 9 AM sharp. Early bird gets the worm!