In my Node/Express.js project I can set the Views Folder globally like so:

app.configure(function() {
    app.set('views', __dirname + '/views');
    .... snip ....
});

...and all my view templates go into the views Folder.

Is it possible to override where Express looks for views on a request by request basis? For instance, something like the following:

app.get('/', function(req, res) {
    res.render('index', { viewFolder: 'otherViews' });
});

The reason I ask is I'm trying to replicate Microsoft ASP.NET MVC's Areas functionality where each Area gets it's own views folder.

The 'views' setting is the root directory, so you should be able to specify a sub-folder in the hierarchy:

app.get('/', function(req, res) {
    res.render('areaName/viewName');
});

It means your 'areas' need to be sub-folders, but it allows you to accomplish the separation you are looking for.