What type of menu is this?

[Gidgetstarbaby]

Hi there
Just wondering if you could tell me what the type of list that is used as the main menu on the left hand side of this site:
http://www.dickenschristmasparty.co.uk/

Just wanting to know what that type of menu's called. Is it a unordered list with a hover effect?

Have tried replicating CSS from viewing the page source but to no avail.
Thanks in advance.
Gidgetstarbaby.

[hsriat]

a (line 15)
{
text-decoration: underline;
color: white;
}
.menu_party (line 44)
{
background-image: url(/images/menu/party.jpg);
}
a:hover (line 16)
{
text-decoration: underline;
color: #9d8d32;
}
#menu li a (line 39)
{
display: block;
width: 218px;
height: 40px;
background-position: left top;
background-repeat: no-repeat;
text-indent: -10000px;
overflow-x: hidden;
overflow-y: hidden;
}
#menu li a:hover (line 40)
{
background-position: left bottom;
}

Its using background image in each menu item, and when hovered, its position is shifted to show the other part of the same image.