You cannot train yourself to not be bored. I have a friend who once entertained herself for half an hour with a penny. Everybody has a different attention span. Some of us can find entertainment and stimulation in more areas than others, for varying lengths of time. The best you can do is figure out where your interests lie and pursue them.
I can tell you that I live at home, do not drive, do not have a job, and have been home for the majority of my summer – I have rarely been bored.
The Internet alone is a vast well of information and connectivity (and since you are here on Fluther, I assume you have Internet access.) It’s easy to search your interests and connect with others who share your interests if you know where to look :)