You can invest in funds, where you can get out profit each month, so you can have cash for living. Or you can invest and then monthly profit also invest on auto mode. 
yes investing is good way to place your money so you get money for a living each month
gambling and loans sites are pretty risky ones but they can give you lots of profit, so that might be great way to use your bitcoins, or you can just keep them for while till they'll get expensive
Well said you can create your own gambling website. I have seen gambling websites to be the one in which most bitcoin users spent lot time.