SO collapse menu example
HTML
<link rel="stylesheet" href="http://netdna.bootstrapcdn.com/twitter-bootstrap/2.2.2/css/bootstrap-combined.min.css">
<script src="http://netdna.bootstrapcdn.com/twitter-bootstrap/2.2.2/js/bootstrap.min.js"></script>
<script src=" http://twitter.github.com/bootstrap/assets/js/bootstrap-tooltip.js"></script>
<div class="navbar">
<div class="navbar-inner">
<div class="container">
<!-- .btn-navbar is used as the toggle for collapsed navbar content -->
<a class="btn btn-navbar" data-toggle="collapse" data-target=".nav-collapse">
<span class="icon-globe"></span>
</a>
<!-- Be sure to leave the brand out there if you want it shown -->
<a class="brand" href="#">Project name</a>
<!-- Everything you want hidden at 940px or less, place within here -->
<div class="nav-collapse collapse">
<!-- .nav, .navbar-search, .navbar-form, etc -->
</div>
</div>
</div>
</div>
CSS
body{margin-top:20px}