[destus]

<style>
        .block {
            width: 200px;
            height: 100px;
            border: 2px solid #ccc;
        }

        .active {
            background: #ccc;
        }
    </style>
<script src="http://code.jquery.com/jquery-latest.min.js"></script>
    <script>
        $(function () {
            var txt = $('.block').children('p').html();

            $('.block').on('click', function (event) {

                $(this).toggleClass('active');
                ($('.block').children('p').html() == txt) ? $('.block').children('p').text('Тратата') : $('.block').children('p').html(txt);
            });
           
        })
    </script>

    <div class="block">
        <p><a href="#">Bla-bla</a></p>
    </div>