How do u put a timer on a website so every 10 minutes it make a DIFFERENT site pop-up

for example lets say the websites i want to popup every 10 minutes are:
http://a.b.c
http://1.2.3
http://1.a.3
http://1.2.c

i want to make it so that when some1 visits the main site, those sites will pop-up every 10 mintues(1 of the sites every 10 minutes)