Animation
And finally just for Safari users or Firefox 4 beta users we have transitions. Transitions include rotation, easing in and out of elements and the ability to specify how many times they do this... and much more!

A simple example might include changing the hover effect of a link so the colour changes smoothly from one colour to another.

Both Safari and Firefox 4 support this functionality consistenly.

First define a link colour:

.box a {
color: #0f0;
}

Set a colour and the property to animate using the transition-property:

#box10 a:hover {
color: #0f0;
-moz-transition-property: color;
-webkit-transition-property: color;
}

How long should the animation last:

#box10 a:hover {
color: #0f0;
-moz-transition-property: color;
-webkit-transition-property: color;
-moz-transition-duration: 0.5s;
-webkit-transition-duration: 0.5s;
}

What animation type should be used (including ease, linear, ease-in, ease-out and more!):

Links can be made to have subtle transitions using the transition CSS commands

#box10 a:hover {
color:#31801f;
-moz-transition-property: color;
-webkit-transition-property: color;
-moz-transition-duration: 0.5s;
-webkit-transition-duration: 0.5s;
-moz-transition-timing-function: ease;
-webkit-transition-timing-function: ease;
}

There are many more ways to animate elements and the CSS3 transition working draft outlines these in great detail.