reveal.js 
A framework for easily creating beautiful presentations using HTML. Check out the live demo.
reveal.js comes with a broad range of features including nested slides, markdown contents, PDF export, speaker notes and a JavaScript API. It's best viewed in a browser with support for CSS 3D transforms but fallbacks are available to make sure your presentation can still be viewed elsewhere.
More reading in the Wiki:
- Changelog: Up-to-date version history.
- Examples: Presentations created with reveal.js, add your own!
- Browser Support: Explanation of browser support and fallbacks.
rvl.io
Slides are written using HTML or markdown but there's also an online editor for those of you who prefer a more traditional user interface. Give it a try at www.rvl.io.
Instructions
Markup
Markup heirarchy needs to be <div class="reveal"> <div class="slides"> <section> where the <section> represents one slide and can be repeated indefinitely. If you place multiple <section>'s inside of another <section> they will be shown as vertical slides. The first of the vertical slides is the "root" of the others (at the top), and it will be included in the horizontal sequence. For example:
<div class="reveal">
<div class="slides">
<section>Single Horizontal Slide</section>
<section>
<section>Vertical Slide 1</section>
<section>Vertical Slide 2</section>
</section>
</div>
</div>Markdown
It's possible to write your slides using Markdown. To enable Markdown, add the data-markdown attribute to your <section> elements and wrap the contents in a <script type="text/template"> like the example below.
This is based on data-markdown from Paul Irish which in turn uses showdown. Sensitive to indentation (avoid mixing tabs and spaces) and line breaks (avoid consecutive breaks).
<section data-markdown>
<script type="text/template">
## Page title
A paragraph with some text and a [link](http://hakim.se).
</script>
</section>External Markdown
You can write your content as a separate file and have reveal.js load it at runtime. Note the separator arguments which determine how slides are delimited in the external file.
<section data-markdown="example.md" data-separator="^\n\n\n" data-vertical="^\n\n"></section>Configuration
At the end of your page you need to initialize reveal by running the following code. Note that all config values are optional and will default as specified below.