Developing simple, not bloated (minimal), blazing fast native apps (have done that in Android so far) is the major interest.
I had previously listed RIA, NLP, ML and those were from almost 10-15 years ago, or maybe possibly from when I was still in college. Those were fascinating things for at that time. What interests me now technically? Something that makes human interactions with software systems easier. That might be good UX and turning a good design or idea into a reality in the form of an app, or working with a backend team to come up with useful APIs and interfaces that will help in that becoming possible. Ideas that result into or may result into technologies that directly and in simple ways interact with individual users, that interests me. A backup tool, or service, an email client, an app or SDK that helps people verify themselves when opening a bank account, or applying for a loan, a letter writing/pen pal platform - you get the drift. Also, a complex system that presents itself in accessible ways to the end users. Things like that.