I've been working at my company for almost a year now. A few months after I started, there has been talk of developing a lunch order application mainly for internal use (optionally as free bonus for another product we sell), with me being the only developer, as a training exercise. I started work on analysis, but after a few days, my boss had another assignment ready, which lasted until early this year.
now, this internal application has been somewhat of a running gag in our company. the employee who was hired before me said there were also talks of him developing this app. The coworker who was hired after me also was mentioned in this app. I heard that this app has dated back to the foundation of the company, and likely would never be built, sometimes being mentioned but never actually started on because it is not profitable. It's basically vaporware, a mythical product that may never been released.
However, at home I'm currently in a period of boredom, and I've been thinking about developing this project personally, sort of as a surprise for my boss. to clarify: I will not tell my boss about this until I have a working prototype, although I will ask one of my coworkers what he thinks about it. the issue is that we mainly develop for the Dynamics CRM platform, and this app would be developed on there as well, so I will need permission to use our development environment for this.
I'm wondering what the advantages and disadvantages of doing this project in my private time is if I don't tell my boss (he's not on SE, so I doubt he'd find out this way). Are there mainly advantages, or is there some huge disadvantage that could get me into trouble?