Are you bored? Color blind? Or you can't seems to push your self to click on boring links? Well, place this .js in your custom header.
Create .js file called rainbow.js
var rate = 20; // Increase amount(The degree of the transmutation)


////////////////////////////////////////////////////////////////////
// Main routine

if (document.getElementById)
window.onerror=new Function("return true")

var objActive; // The object which event occured in
var act = 0; // Flag during the action
var elmH = 0; // Hue
var elmS = 128; // Saturation
var elmV = 255; // Value
var clrOrg; // A color before the change
var TimerID; // Timer ID


if (document.all) {
document.onmouseover = doRainbowAnchor;
document.onmouseout = stopRainbowAnchor;
}
else if (document.getElementById) {
document.captureEvents(Event.MOUSEOVER | Event.MOUSEOUT);
document.onmouseover = Mozilla_doRainbowAnchor;
document.onmouseout = Mozilla_stopRainbowAnchor;
}


//=============================================================================
// doRainbow
// This function begins to change a color.
//=============================================================================
function doRainbow(obj)
{
if (act == 0) {
act = 1;
if (obj)
objActive = obj;
else
objActive = event.srcElement;
clrOrg = objActive.style.color;
TimerID = setInterval("ChangeColor()",100);
}
}


//=============================================================================
// stopRainbow
// This function stops to change a color.
//=============================================================================
function stopRainbow()
{
if (act) {
objActive.style.color = clrOrg;
clearInterval(TimerID);
act = 0;
}
}


//=============================================================================
// doRainbowAnchor
// This function begins to change a color. (of a anchor, automatically)
//=============================================================================
function doRainbowAnchor()
{
if (act == 0) {
var obj = event.srcElement;
while (obj.tagName != 'A' && obj.tagName != 'BODY') {
obj = obj.parentElement;
if (obj.tagName == 'A' || obj.tagName == 'BODY')
break;
}

if (obj.tagName == 'A' && obj.href != '') {
objActive = obj;
act = 1;
clrOrg = objActive.style.color;
TimerID = setInterval("ChangeColor()",100);
}
}
}


//=============================================================================
// stopRainbowAnchor
// This function stops to change a color. (of a anchor, automatically)
//=============================================================================
function stopRainbowAnchor()
{
if (act) {
if (objActive.tagName == 'A') {
objActive.style.color = clrOrg;
clearInterval(TimerID);
act = 0;
}
}
}


//=============================================================================
// Mozilla_doRainbowAnchor(for Netscape6 and Mozilla browser)
// This function begins to change a color. (of a anchor, automatically)
//=============================================================================
function Mozilla_doRainbowAnchor(e)
{
if (act == 0) {
obj = e.target;
while (obj.nodeName != 'A' && obj.nodeName != 'BODY') {
obj = obj.parentNode;
if (obj.nodeName == 'A' || obj.nodeName == 'BODY')
break;
}

if (obj.nodeName == 'A' && obj.href != '') {
objActive = obj;
act = 1;
clrOrg = obj.style.color;
TimerID = setInterval("ChangeColor()",100);
}
}
}


//=============================================================================
// Mozilla_stopRainbowAnchor(for Netscape6 and Mozilla browser)
// This function stops to change a color. (of a anchor, automatically)
//=============================================================================
function Mozilla_stopRainbowAnchor(e)
{
if (act) {
if (objActive.nodeName == 'A') {
objActive.style.color = clrOrg;
clearInterval(TimerID);
act = 0;
}
}
}


//=============================================================================
// Change Color
// This function changes a color actually.
//=============================================================================
function ChangeColor()
{
objActive.style.color = makeColor();
}


//=============================================================================
// makeColor
// This function makes rainbow colors.
//=============================================================================
function makeColor()
{
// Don't you think Color Gamut to look like Rainbow?

// HSVtoRGB
if (elmS == 0) {
elmR = elmV; elmG = elmV; elmB = elmV;
}
else {
t1 = elmV;
t2 = (255 - elmS) * elmV / 255;
t3 = elmH % 60;
t3 = (t1 - t2) * t3 / 60;

if (elmH < 60) {
elmR = t1; elmB = t2; elmG = t2 + t3;
}
else if (elmH < 120) {
elmG = t1; elmB = t2; elmR = t1 - t3;
}
else if (elmH < 180) {
elmG = t1; elmR = t2; elmB = t2 + t3;
}
else if (elmH < 240) {
elmB = t1; elmR = t2; elmG = t1 - t3;
}
else if (elmH < 300) {
elmB = t1; elmG = t2; elmR = t2 + t3;
}
else if (elmH < 360) {
elmR = t1; elmG = t2; elmB = t1 - t3;
}
else {
elmR = 0; elmG = 0; elmB = 0;
}
}

elmR = Math.floor(elmR).toString(16);
elmG = Math.floor(elmG).toString(16);
elmB = Math.floor(elmB).toString(16);
if (elmR.length == 1) elmR = "0" + elmR;
if (elmG.length == 1) elmG = "0" + elmG;
if (elmB.length == 1) elmB = "0" + elmB;

elmH = elmH + rate;
if (elmH >= 360)
elmH = 0;

return '#' + elmR + elmG + elmB;
}
Add it to your base directory.
In Custom header add this
<script src="rainbow.js"></script>