Edit in JSFiddle

//extend the A object with Backbone.Events methods
var A = _.extend({name:'A'}, Backbone.Events);

var foo = function () {
    console.log('foo');
};
var bar = function () {
    console.log('bar');
};

A.on('log',foo);
A.on('log',bar);

A.trigger('log'); //logs foo then bar
A.off('log'); //remove log event
A.trigger('log'); //logs nothing, all log events were removed