Rotating Header Images?

Is there a way to have a different header image load for every time someone visits the site? Is there fairly simple code for something like that?

Here’s my header code from stylesheet.php:

/* Header and wrapper */
#wrapper {
  margin: 0 auto;
  width: 960px;
  text-align: left;
  padding: 0;
  }

#header {
  padding: 0;
  margin: 0;
  height: 80px;
  }

#header #topright {
  text-align: right;
  float: right;
  width: 600px;
  margin: 5px 0 0 0;
}
#header #topright ul {
  list-style: none;
  padding: 0;
  margin: 0;
  }
#header #topright li {
  display: inline;
  }
#header #topright li a {
  color: #fff;
  font-size: 9pt;
  padding: 0 0 0 25px;
  text-transform: lowercase;
  }
#header #topright li a:hover {
  color: #000;
  text-decoration: none;
  }

#header #logo {
  background:url(images/logo.gif) no-repeat;
  height:100%;
    float: left;
  width: 977px;
  height: 160px;
  margin: 25px 0 0 0;
  padding: 0;
}
#header h1 {
  padding: 0;
  margin: 0;
  }
#header h1 a {
  color: #fff;
  font-size: 17pt;
  text-decoration: none;
  }
#header h1 a:hover {
  color: #eee;
  text-decoration: none;
  }
#header span {
  padding: 0;
  color: #111;
  font-size: 11pt;
  }

Thanks!