Menu and SideBar Slides, Fades, and Hides
This code can use quite a bit of work.


Run this code through a beautifier, ideally prior to posting it to codereview ;)
You are repeating yourself a lot, example : 



// Sidebar tab highlight when clicked
$("#sidebar-tabs-container table td").click(function() {
  $("#sidebar-tabs-container table td").removeClass("sidebar-tab-selected");
  $(this).addClass("sidebar-tab-selected");
});



Unless you have a dynamic number of sidebar tabs ( seems unlikely ), you can do the following.

var $sidebarTabs  = $('#sidebar-tabs-container table td');
var selectedClass = 'sidebar-tab-selected';

$sidebarTabs.click(function() {
  $sidebarTabs.removeClass( selectedClass );
  $(this).addClass( selectedClass );
});


The interesting part is that you do this type of code twice, so you could also write a helper.

function wireClassToggler( elements, className )
{
  elements.click(function()
  {
    elements.removeClass( className );
    $(this).addClass( className );
  });
}

wireClassToggler( $('#sidebar-tabs-container table td'), 'sidebar-tab-selected' );
wireClassToggler( $('#activity-media-icons-container span'), 'activity-new-media-icon-clicked' );


You also seem to use copy pasted code for the slideUp and slideDown functions, you should generalize that as well.