y = 0;
ad = new Array(y);
ad[y++] = '<a href="http://cendeac.net/" target="new"><img src="http://salonkritik.net/ads/cendeac.gif" border="0"></a>'
ad[y++] = '<a href="http://www.museoreinasofia.es/" target="new"><img src="http://salonkritik.net/ads/mncars.gif" border="0"></a>'
ad[y++] = '<a href="http://www.montehermoso.net/" target="new"><img src="http://salonkritik.net/ads/montehermoso.gif" border="0"></a>'
ad[y++] = '<a href="http://www.fundacion.telefonica.com/" target="new"><img src="http://salonkritik.net/ads/fund_telefonica.jpg" border="0"></a>'
ad[y++] = '<a href="http://www.cgac.org/" target="new"><img src="http://salonkritik.net/ads/cGac.gif" border="0"></a>'
x = Math.floor(Math.random()*(y));
document.write(ad[x]);