the time until...

timetil.js

function timeTil(date) {
    var t = [
            [60 * 60 * 24 * 7 * 4 * 12, 'year'],
            [60 * 60 * 24 * 7 * 4, 'month'],
            [60 * 60 * 24 * 7, 'week'],
            [60 * 60 * 24, 'day'],
            [60 * 60, 'hour'],
            [60, 'minute'],
            [1, 'second']
        ],
        now = +new Date,
        then,
        diff,
        secs;

    if (typeof date === 'string') {
        then = +new Date(date);
    } else if (date.getTime && typeof date.getTime === 'function') {
        then = +date;
    }

    diff = then - now;
    secs = diff / 1000;

    function getChunk(secs, lastChunk) {
        var chunk,
            name,
            remainder,
            til,
            chunkTil = lastChunk || '',
            i, j;

        for (i = 0, j = t.length; i < j; i++) {
            chunk = t[i][0];
            name  = t[i][1];

            if (~~(secs / chunk) !== 0) {
                remainder = secs % chunk;
                break;
            }
        }
        til = Math.round(secs / chunk);

        chunkTil += til + ' ' + name + (til > 1 ? 's ' : ' ');

        return (remainder > 1) ? getChunk(remainder, chunkTil) : chunkTil;
    }

    return getChunk(secs);
}

console.log(timeTil('8/27/2011'));
console.log(timeTil(new Date(2012)));