Edit in JSFiddle

(function(R) {
    var incomplete = R.filter(R.where({complete: false}));
    var sortByDate = R.sortBy(R.prop('dueDate'));
    var sortByDateDescend = R.compose(R.reverse, sortByDate);
    var importantFields = R.project(['title', 'dueDate']);
    var groupByUser = R.partition(R.prop('username'));
    var activeByUser = R.compose(groupByUser, incomplete);
    var gloss = R.compose(importantFields, R.take(5), sortByDateDescend);
    var topData = R.compose(gloss, incomplete);
    var topDataAllUsers = R.compose(R.mapObj(gloss), activeByUser);
    var byUser = R.use(R.filter).over(R.propEq("username"));
    
    log("Gloss for Scott:");
    log(topData(byUser("Scott", tasks)));
    log("====================");
    log("Gloss for everyone:");
    log(topDataAllUsers(tasks));
}(ramda));

<pre><code id="output"></code></pre>
<script>
var log = (function() {
    var o = document.getElementById("output");
    return function(obj) {o.innerHTML += "\n" + JSON.stringify(obj, null, 4);}
}()); 
var tasks = [
    {username: 'Michael', title: 'Curry stray functions', dueDate: '2014-05-06', 
               complete: true, effort: 'low', priority: 'low'},    
    {username: 'Scott', title: 'Add `fork` function', dueDate: '2014-05-14', 
               complete: true, effort: 'low', priority: 'low'},    
    {username: 'Michael', title: 'Write intro doc', dueDate: '2014-05-16', 
               complete: true, effort: 'low', priority: 'low'},    
    {username: 'Michael', title: 'Add modulo function', dueDate: '2014-05-17', 
               complete: false, effort: 'low', priority: 'low'},    
    {username: 'Michael', title: 'Separating generators', dueDate: '2014-05-24', 
               complete: false, effort: 'medium', priority: 'medium'},
    {username: 'Scott', title: 'Fold algebra branch back in', dueDate: '2014-06-01', 
               complete: false, effort: 'low', priority: 'low'},
    {username: 'Scott', title: 'Fix `and`/`or`/`not`', dueDate: '2014-06-05', 
               complete: false, effort: 'low', priority: 'low'},
    {username: 'Michael', title: 'Types infrastucture', dueDate: '2014-06-06', 
               complete: false, effort: 'medium', priority: 'high'},
    {username: 'Scott', title: 'Add `mapObj`', dueDate: '2014-06-09', 
               complete: false, effort: 'low', priority: 'medium'}, 
    {username: 'Scott', title: 'Write using doc', dueDate: '2014-06-11', 
               complete: false, effort: 'medium', priority: 'high'},
    {username: 'Michael', title: 'Finish algebraic types', dueDate: '2014-06-15', 
               complete: false, effort: 'high', priority: 'high'},
    {username: 'Scott', title: 'Determine versioning scheme', dueDate: '2014-06-15', 
                complete: false, effort: 'low', priority: 'medium'},
    {username: 'Michael', title: 'Integrate types with main code', dueDate: '2014-06-22', 
               complete: false, effort: 'medium', priority: 'high'},
    {username: 'Richard', title: 'API documentation', dueDate: '2014-06-22', 
               complete: false, effort: 'high', priority: 'medium'},
    {username: 'Scott', title: 'Complete build system', dueDate: '2014-06-22', 
               complete: false, effort: 'medium', priority: 'high'},
    {username: 'Richard', title: 'Overview documentation', dueDate: '2014-06-25', 
               complete: false, effort: 'medium', priority: 'high'}
];
</script>