So, a requirement of a recent project of mine was to create a "Metro"-themed website. I really wanted those nice loaders that you get with Microsoft applications today and thought it's probably possible with CSS3. And it is!
Check it out on JSFiddle and let me know what you think and whether there are any improvements you can think of. I've added support for the browsers that support transitions so the code is currently fairly bloated but using a CSS pre-processor you can avoid this headache.
For an example here check out the below!
Nice work! What are all the additional dancing-dots-slideXX keyframes for?