There are tons of activities for National Novel Writing Month but the most important is that pesky writing thing. To help with that you can use an online application like Write or Die to do some solo speed writing. You set the time and/or word count you'd like to reach and then select your consequence settings. During the time you must continually type or you will receive a negative consequence.
Write or Die really does put the prod in productivity with multiple consequence settings and a timer.
Track your progress! This will help you see how far you've come and how much you still need to accomplish. It's a great way to procrastinate too! There are loads of fancy and simple ones on the internet if you run a quick Google search.
I found this one on deviantART: NaNoWriMo 2011 tracker
2014 Update: You may need to google search this or browse through the forum at NaNoWriMo's website: nanowrimo.org/forums/helpful-r…
Another tip is to browse on your phone's app store for word count trackers as many have popped up in the last couple years.
These are great ways to watch for events, receive pep talks, or find a support buddy. A lot of lit groups are NaNo friendly. Check your current groups for events and resources!
These awesome groups exist purely for NaNo related activities:WriMo-Writers
2014 Update: CRLiterature - Not solely for NaNo but extremely likely to be a beneficial resource for events and updates on dA NaNo happenings.
The NaNoWriMo chatroom on deviantART has been recommended by several reputable deviants.
2014 Edit: WordWars may be a place to check out for writing events. If you need to log some writing time the Chat Tour is a great place to do it. While playing Word Wars you'll have a chance to win awesome prizes and boost your word count.