How can I gain weight?

I'm 20 years old 5'7'' and 110 pounds. I have a pretty lazy lifestyle. I play videos a lot and spend more than a healthy amount of time on the computer and games and such. I'm more then willing to give up gaming time to get in shape, so that's not an issue. I have a very fast metabolism and have always been skinny, but at this point in my life I kinda want to get into the normal range weight for someone of my height, which is around 125-135.

What is a good weight gainer for someone with my body type? Or should I even be taking a weight gainer? If not, what supplement should I be taking while working out.

In the past, through working out, I've been able to build a lot of endurance and strength, but not much visible results. I'm looking for something that will make me bigger faster, instead of strong endurance.