Expanded version of this: https://gist.github.com/j127/7191906 -- just run npm install mongoose in the terminal to install the database stuff.

Save Tweets to MongoDB

// Import the twit module that was downloaded with npm install twit.
// The module is loaded in node_modules and Node.js knows where to find it.
var Twit = require('twit');

// Import the MongoDB connection stuff
var mongoose = require('mongoose');

// Connect to the database - this also creates the database if it doesn't exist
mongoose.connect('mongodb://localhost/twittersearch');

// Define the DB schema
var Tweet = mongoose.model('Tweet', { tweettext: String });

// Settings -- put your keys here:
var T = new Twit({
    consumer_key: '...',
    consumer_secret: '...',
    access_token: '...',
    access_token_secret: '...'
});

// A method to search tweets. This will search for five JavaScript tweets from 2013.
T.get('search/tweets', { q: 'javascript since:2013-01-01', count: 5 }, function(err, reply) {
    var tweet, tweets, currentTweet, i,  len;

    // Uncomment the next line to view the JSON that is returned
    // console.log(reply);

    // Extract the statuses
    tweets = reply.statuses;

    // Loop over the statuses
    for (i = 0, len = tweets.length; i < len; i++) {
        // Get the text
        currentTweet = tweets[i].text;  

        // Prepare tweet for the database
        tweet = new Tweet( { tweettext: currentTweet } );

        tweet.save(function (err) {
            if (err) {
                console.log(err);
            }
            // Success:
            console.log('Tweet saved: ' + currentTweet);
        });
    }
});