1. Meet old friends and acquaintances for lunch, dinner or drinks. Your friends have friends, many that you don't already know. The more you tell people about what you want to do, the more they can help you. It doesn't cut it to just say "I want a career in finance". You need to be much more specific, really explaining what you are looking for in a job. Even if you already have your job lined up, this is a great opportunity to broadcast what you will be doing and to make connections for future business partnerships. This could be starting relationships with future clients or suppliers, or even future job opportunities.
2. Meet new friends. Use this time to ask for informational interviews with people you've been meaning to connect with (yes, I know you have been really trying to do this but have been way too busy....). You have two weeks in which you should be able to fit several 20-30 minute meetings that may help you out along the way. Hopefully they go well and remember to ask for suggestions on how to continue to expand your network (you want to get at least 1-2 more names from each of your meetings). Even if you already have a job, use this time to network with others in your intended field to find out more about what you will be doing for at least the next few years of your life.
3. Look into professional organizations in the area you are going into or the area you would like to go into for your full time career. If you happen to be in the city you are going to live in (or want to live in), spend some time on the web looking up organizations that tie to what you want to do. For example, if you want to go into business marketing, look up the many different organizations that exist for marketing professionals. They might even be having an event while you are home. Most organizations will let you come to check out what they do, so give them a call and ask. You never know who you might end up talking to or sitting next to at a table.