Only problem I can see is that you have .show.slideUp both. You only need .slideUp to hide, and .slideDown to show.
<script type="text/javascript">
$(document).ready(function(){
$("#Services").click(function(event){
$(".magicDiv").slideUp("slow");
});
});
</script>
Conversely, if you want a slightly nicer effect, attach the jQuery UI as well as jQuery itself, and then use:
<script type="text/javascript">
$(document).ready(function(){
$("#Services").click(function(event){
$(".magicDiv").hide("slide", { direction: "up" }, 800); //To hide
$(".magicDiv").show("slide", { direction: "up" }, 800); //To show
});
});
</script>