These HTML5 skeletons and frameworks are very helpful for starting out new web development projects.

HTML5 Frameworks:

Basic HTML5 Skeletons

Smashing Magazine HTML5 Layout

Source

index.html:

<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8" />
<title>Smashing HTML5!</title>

<link rel="stylesheet" href="css/main.css" type="text/css" />

<!--[if IE]>
  <script src="http://html5shiv.googlecode.com/svn/trunk/html5.js"></script><![endif]-->
<!--[if lte IE 7]>
  <script src="js/IE8.js" type="text/javascript"></script><![endif]-->
<!--[if lt IE 7]>
  <link rel="stylesheet" type="text/css" media="all" href="css/ie6.css"/><![endif]-->
</head>

<body id="index" class="home">

<header id="banner" class="body">
  <h1><a href="#">Smashing HTML5! <strong>HTML5 in the year <del>2022</del> <ins>2009</ins></strong></a></h1>

  <nav><ul>
    <li class="active"><a href="#">home</a></li>
    <li><a href="#">portfolio</a></li>

    <li><a href="#">blog</a></li>
    <li><a href="#">contact</a></li>
  </ul></nav>

</header><!-- /#banner -->  

<aside id="featured" class="body"><article>
  <figure>
    <img src="images/temp/sm-logo.gif" alt="Smashing Magazine" />
  </figure>
  <hgroup>

    <h2>Featured Article</h2>
    <h3><a href="#">HTML5 in Smashing Magazine!</a></h3>
  </hgroup>
  <p>Discover how to use Graceful Degradation and Progressive Enhancement techniques to achieve an outstanding, cross-browser <a href="http://dev.w3.org/html5/spec/Overview.html" rel="external">HTML5</a> and <a href="http://www.w3.org/TR/css3-roadmap/" rel="external">CSS3</a> website today!</p>

</article></aside><!-- /#featured -->

<section id="content" class="body">
  <ol id="posts-list" class="hfeed">
    <li><article class="hentry">  
      <header>
        <h2 class="entry-title"><a href="#" rel="bookmark" title="Permalink to this POST TITLE">This be the title</a></h2>

      </header>

      <footer class="post-info">
        <abbr class="published" title="2005-10-10T14:07:00-07:00"><!-- YYYYMMDDThh:mm:ss+ZZZZ -->
          10th October 2005
        </abbr>

        <address class="vcard author">

          By <a class="url fn" href="#">Enrique Ramírez</a>
        </address>
      </footer><!-- /.post-info -->

      <div class="entry-content">

        <p>Lorem ipsum dolor sit amet, consectetur adipiscing elit. Quisque venenatis nunc vitae libero iaculis elementum. Nullam et justo <a href="#">non sapien</a> dapibus blandit nec et leo. Ut ut malesuada tellus.</p>
      </div><!-- /.entry-content -->
    </article></li>

    <li><article class="hentry">
      ...
    </article></li>

    <li><article class="hentry">
      ...
    </article></li>

  </ol><!-- /#posts-list -->
</section><!-- /#content -->

<section id="extras" class="body">
  <div class="blogroll">
    <h2>blogroll</h2>

    <ul>
      <li><a href="#" rel="external">HTML5 Doctor</a></li>
      <li><a href="#" rel="external">HTML5 Spec (working draft)</a></li>

      <li><a href="#" rel="external">Smashing Magazine</a></li>
      <li><a href="#" rel="external">W3C</a></li>
      <li><a href="#" rel="external">Wordpress</a></li>

      <li><a href="#" rel="external">Wikipedia</a></li>
      <li><a href="#" rel="external">HTML5 Doctor</a></li>
      <li><a href="#" rel="external">HTML5 Spec (working draft)</a></li>

      <li><a href="#" rel="external">Smashing Magazine</a></li>
      <li><a href="#" rel="external">W3C</a></li>
      <li><a href="#" rel="external">Wordpress</a></li>

      <li><a href="#" rel="external">Wikipedia</a></li>
      <li><a href="#" rel="external">HTML5 Doctor</a></li>
      <li><a href="#" rel="external">HTML5 Spec (working draft)</a></li>

      <li><a href="#" rel="external">Smashing Magazine</a></li>
      <li><a href="#" rel="external">W3C</a></li>
      <li><a href="#" rel="external">Wordpress</a></li>

      <li><a href="#" rel="external">Wikipedia</a></li>
    </ul>
  </div><!-- /.blogroll -->

  <div class="social">

    <h2>social</h2>
    <ul>
      <li><a href="http://delicious.com/enrique_ramirez" rel="me">delicious</a></li>
      <li><a href="http://digg.com/users/enriqueramirez" rel="me">digg</a></li>

      <li><a href="http://facebook.com/enrique.ramirez.velez" rel="me">facebook</a></li>
      <li><a href="http://www.lastfm.es/user/enrique-ramirez" rel="me">last.fm</a></li>
      <li><a href="http://website.com/feed/" rel="alternate">rss</a></li>

      <li><a href="http://twitter.com/enrique_ramirez" rel="me">twitter</a></li>
    </ul>
  </div><!-- /.social -->
</section><!-- /#extras -->

<footer id="contentinfo" class="body">
  <address id="about" class="vcard body">
    <span class="primary">
      <strong><a href="#" class="fn url">Smashing Magazine</a></strong>

      <span class="role">Amazing Magazine</span>
    </span><!-- /.primary -->

    <img src="images/avatar.gif" alt="Smashing Magazine Logo" class="photo" />
    <span class="bio">Smashing Magazine is a website and blog that offers resources and advice to web developers and web designers. It was founded by Sven Lennartz and Vitaly Friedman.</span>

  </address><!-- /#about -->
  <p>2005-2009 <a href="http://smashingmagazine.com">Smashing Magazine</a>.</p>
</footer><!-- /#contentinfo -->

</body>
</html>

main.css:

/*
  Name: Smashing HTML5
  Date: July 2009
  Description: Sample layout for HTML5 and CSS3 goodness.
  Version: 1.0
  Author: Enrique Ramírez
  Autor URI: http://enrique-ramirez.com
*/

/* Imports */
@import url("reset.css");
@import url("global-forms.css");

/***** Global *****/
/* Body */
  body {
    background: #F5F4EF url('../images/bg.png');
    color: #000305;
    font-size: 87.5%; /* Base font size: 14px */
    font-family: 'Trebuchet MS', Trebuchet, 'Lucida Sans Unicode', 'Lucida Grande', 'Lucida Sans', Arial, sans-serif;
    line-height: 1.429;
    margin: 0;
    padding: 0;
    text-align: left;
  }

/* Headings */
h2 {font-size: 1.571em} /* 22px */
h3 {font-size: 1.429em} /* 20px */
h4 {font-size: 1.286em} /* 18px */
h5 {font-size: 1.143em} /* 16px */
h6 {font-size: 1em} /* 14px */

h2, h3, h4, h5, h6 {
  font-weight: 400;
  line-height: 1.1;
  margin-bottom: .8em;
}

/* Anchors */
a {outline: 0;}
a img {border: 0px; text-decoration: none;}
a:link, a:visited {
  color: #C74350;
  padding: 0 1px;
  text-decoration: underline;
}
a:hover, a:active {
  background-color: #C74350;
  color: #fff;
  text-decoration: none;
  text-shadow: 1px 1px 1px #333;
}

/* Paragraphs */
p {margin-bottom: 1.143em;}
* p:last-child {margin-bottom: 0;}

strong, b {font-weight: bold;}
em, i {font-style: italic;}

::-moz-selection {background: #F6CF74; color: #fff;}
::selection {background: #F6CF74; color: #fff;}

/* Lists */
ul {
  list-style: outside disc;
  margin: 1em 0 1.5em 1.5em;
}

ol {
  list-style: outside decimal;
  margin: 1em 0 1.5em 1.5em;
}

dl {margin: 0 0 1.5em 0;}
dt {font-weight: bold;}
dd {margin-left: 1.5em;}

/* Quotes */
blockquote {font-style: italic;}
cite {}

q {}

/* Tables */
table {margin: .5em auto 1.5em auto; width: 98%;}

  /* Thead */
  thead th {padding: .5em .4em; text-align: left;}
  thead td {}

  /* Tbody */
  tbody td {padding: .5em .4em;}
  tbody th {}

  tbody .alt td {}
  tbody .alt th {}

  /* Tfoot */
  tfoot th {}
  tfoot td {}

reset.css

/* http://meyerweb.com/eric/tools/css/reset/ 
   v2.0 | 20110126
   License: none (public domain)
*/

html, body, div, span, applet, object, iframe,
h1, h2, h3, h4, h5, h6, p, blockquote, pre,
a, abbr, acronym, address, big, cite, code,
del, dfn, em, img, ins, kbd, q, s, samp,
small, strike, strong, sub, sup, tt, var,
b, u, i, center,
dl, dt, dd, ol, ul, li,
fieldset, form, label, legend,
table, caption, tbody, tfoot, thead, tr, th, td,
article, aside, canvas, details, embed, 
figure, figcaption, footer, header, hgroup, 
menu, nav, output, ruby, section, summary,
time, mark, audio, video {
    margin: 0;
    padding: 0;
    border: 0;
    font-size: 100%;
    font: inherit;
    vertical-align: baseline;
}
/* HTML5 display-role reset for older browsers */
article, aside, details, figcaption, figure, 
footer, header, hgroup, menu, nav, section {
    display: block;
}
body {
    line-height: 1;
}
ol, ul {
    list-style: none;
}
blockquote, q {
    quotes: none;
}
blockquote:before, blockquote:after,
q:before, q:after {
    content: '';
    content: none;
}
table {
    border-collapse: collapse;
    border-spacing: 0;
}