Exactly what I'm doing right now. I work a 9-5 but there is so much pressure and everyone usually ends up staying longer. Read my previous comments on conditions at my workplace.
On any off time that I have I research current job postings of lucrative startups and compiled a list of all the shit I have to learn and excel that.
I have 3 months left until the end of my contract in which I'm coding the most I possibly can. In the past 3 days I've coded two side projects in mongo/angular/express/node and a bunch of other tech.