H2 is your username at the top of your profile (or cult name on cult pages).

Make It Disappear
<style type="text/css">
h2 { display: none; }
</style>

Borders
To put a border around it:
<style type="text/css">
h2 { border: 1px solid red; }
</style>
[ More Border Styles ]

Text Styles & Filters
To change the style of the text:
<style type="text/css">
h2 {
color: red;
font-size: 18pt;
font-variant: small-caps;
}
</style>
More
[ Text Styles ]
To put a filter on the text (like glow, fade etc):
Nb, filters only work in the IE browser.
<style type="text/css">
h2 { filter: glow(color=deeppink, strength=5); }
</style>
[ More Filters ]

Replacing It With An Image
To replace your heading with an image, you need to know the width and height of your image, then:
<style type="text/css">
h2 {
font-size: 0pt;
color: black;
background: url('http://www.PATH TO YOUR IMAGE.gif');
width: YOUR BG IMAGE WIDTHpx;
height: YOUR BG IMAGE HEIGHTpx;
}
</style>
More on
[ Backgrounds ]

Positioning
To create a bit more space above and/or below your heading, you could give it a margin:
<style type="text/css">
h2 {
margin-top: 100px;
margin-bottom: 60px;
}
</style>