I'll hold it up until the halving (with the hope of increase in value of BTCitcoin), then I'll start to purchase mining rigs afterwards (with half of it only) and the other half I would hire developers to make a interesting android game or application (not necessarily a BTCitcoin game or application but something that would have greater impact among more users) and hoping it would profit in the long term in case it becomes popular.
I like your idea of creating an android application (or even a game although i would like a bitcoin ralated app more) i hope you can be successful in it, but i am not so much a fan of the idea of mining at all, not only mining bitcoin but also mining altcoin, it can be profitable but it is a lot of work and stress.