Blocking selected websites !?

well i got an idiot roommate who just make my laptop suffer every now and then.. he just keep on going to these websites with cyber video chat and thats not only what bothers me.. my biggest consern is that he keeps on clicking on every goddamn ad he sees on a website ( for Exp. you won 10000000 $ and get a free green card things ) and this is worse than going to sites and my laptop pays the price i got 24MB line and now it feels like 56 K ... so is there any program that can block sites that i can select not something fancy i mean a very simple program that ask for which websites u want to block and u enter them and voilla the website doesnt work anymore.. i dont want any program that gives pwords when u open a selected site and stuff.. i tried to do it from my explorer but it doesnt work .. FY i have Visa and i use Google Chrome and i got Kaspersky 2010 internet security .. so HELP !!!