My Internet keeps going off and then back on?

I'm not much for computer things, but I have a computer, iPod, iPad, and iPhone. And the Wi-Fi on all of them keeps turning off for about 10-15 minutes and then comes back on. I tried calling Comcast, which is what we use, and they were only trying to charge us for things that didn't sound necessary. So what should I do? Or better yet, what can I do?

You could reset your modem. There should be a button you can press and youve gotta hold it for about a minute then let go and wait for all the lights on the modem to come back on. You can also unplug the router from the outlet and plug it back in after about a minute. If the problem persists demand that a cable guy comes to your house and fix the problem they don't charge you for that (atleast they don't charge here)