digraph href_test
{
	edge
	[
		color = "blue"
	]
	node_1
	[
		color = "red"
	]
	node_2
	[
		color = "green"
	]
	node_1 -> node_2
	[
		label = <<table border='0'> 			<tr> 				<td href='http://savage.net.au' title='Tool tip'>Hover over label, then click it</td> 			</tr> 		</table>>
	]
}