url = new Array(16);
image = new Array(16);

url[0] = "http://www.twogreatclubs.com/";
image[0] = "images/banners/sac_banner.gif";

url[1] = "http://www.grandeventrentalswa.com";
image[1] = "images/banners/grandevent_banner.jpg";

url[2] = "http://www.philips.com/";
image[2] = "images/banners/philips_banner.jpg";

url[3] = "http://www.repc.com/";
image[3] = "images/banners/repc_banner.jpg";

url[4] = "http://www.blackrapid.com/";
image[4] = "images/banners/blackrapid_banner.jpg";

url[5] = "http://uwmedicine.washington.edu/Patient-Care/Locations/uwmc/Pages/default.aspx";
image[5] = "images/banners/uwmc_banner.jpg";

url[6] = "http://www.chirohealth.org/";
image[6] = "images/banners/wsca_banner.png";

url[7] = "http://www.amtrakcascades.com/";
image[7] = "images/banners/amtrak_banner.jpg";

url[8] = "http://www.asiorders.com/";
image[8] = "images/banners/asi_banner.gif";

url[9] = "http://www.ontherunevents.com/";
image[9] = "images/banners/ontherun_banner.jpg";

url[10] = "http://orthopedics.seattlechildrens.org/?src=marathon_bnr_ortho_sea_468x60_ankle";
image[10] = "images/banners/childrens_banner.jpg";

url[11] = "http://www.blackrapid.com/";
image[11] = "images/banners/blackrapid_banner.jpg";

url[12] = "http://uwmedicine.washington.edu/Patient-Care/Locations/uwmc/Pages/default.aspx";
image[12] = "images/banners/uwmc_banner.jpg";

url[13] = "http://uwmedicine.washington.edu/Patient-Care/Locations/uwmc/Pages/default.aspx";
image[13] = "images/banners/uwmc_banner.jpg";

url[14] = "http://uwmedicine.washington.edu/Patient-Care/Locations/uwmc/Pages/default.aspx";
image[14] = "images/banners/uwmc_banner.jpg";

url[15] = "http://www.praguemarathon.com/?utm_source=seattlemarathon_org&utm_medium=banner_468x60_v6_en&utm_term=foreign&utm_content=&utm_campaign=runczech2012";
image[15] = "images/banners/praguemarathon2012.gif";





//calculate a random index
index = Math.floor(Math.random() * url.length);
document.write("<a href=\"" + url[index] + "\"><img src=\"" + image[index] + "\" /></a>\n");