Define templates using keys:

    Template.register("event-detail",
        '<div class="event-detail">' +
        '  <h2>{{ title }}</h2>' +
        '  <p>{{ description }}</p>' +
        '</div>';
    );

Call templates in code:

    var context = {title: "This is a title", description: "This is a description"};
    $('#event').html(Template.render("event-detail", context));