Here's a bit of javascript experimentation. Mouse over the two (fictitious) links in the following paragraph:
Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Donec sit amet purus luctus neque hendrerit aliquet. Nullam elit. In porta fermentum mauris. Quisque non nulla eu eros ornare nonummy. Donec tempus. Maecenas iaculis dolor. Cras tempus erat iaculis erat. Sed id arcu.
This is done with just CSS, believe it or not. (Thanks, Boris, for the pointer!)