(function() {
  'use strict';

  // Model

  var Task = Backbone.Model.extend({
    defaults: {
      title: 'do something!',
      completed: false
    }
  });

  var task = new Task();

  // View

  var TaskView = Backbone.View.extend({
    tagName: 'li',
    template: _.template($('#task-template').html()),
    render: function () {
      var template = this.template(this.model.toJSON());
      this.$el.html(template);
      return this;
    }
  });

  var taskView = new TaskView({
    model: task
  });

  console.log(taskView.render().el);

  $('body').append(taskView.render().el);

}());

(function() {
  'use strict';

  // Model

  var Task = Backbone.Model.extend({
    defaults: {
      title: 'do something!',
      completed: false
    }
  });

  var task = new Task();

  // View

  var TaskView = Backbone.View.extend({
    tagName: 'li',
    template: _.template($('#task-template').html()),
    render: function () {
      var template = this.template(this.model.toJSON());
      this.$el.html(template);
      return this;
    },
    events: {
      'click': 'sayHello'
    },
    sayHello: function  () {
      alert('Hello!');
    }
  });

  var taskView = new TaskView({
    model: task
  });

  console.log(taskView.render().el);

  $('body').append(taskView.render().el);

}());

Add click event.