What kind of APP would you like to see?

My husband is looking to change careers and get into the technology field. He's just looking for entry-level work to get his foot in the door so he can prove his potential, but all the jobs seem to ask for either a degree or on the job experience, and he just doesn't have either. We never could afford college but he is extremely knowledgeable with all the tech stuff (like building computers and writing code/programming stuff. I don't really understand all what he does with it.). He's really a computer geek to be perfectly honest Being he has no degree and never had an "in" at a tech firm to gain on the job experience to "prove" his knowledge and skills, he came up with an alternative idea to show a potential employer he really does knows what he's doing (and trust me, he does). He is going to build a personal website to highlight his abilities, linked on his resume. He's going to write a (simple) program and wants to write an app (probably for android). He's kind of stuck on what kind of app people would find useful or fun.

Thought I would put it out there and see what kind of app people might want to use that isn't already available or perhaps ideas of types of apps already existing that aren't user friendly he may be able to write a more user-friendly version of? Any ideas are appreciated!