Title is pretty self explanatory, but the catch is that the following are NOT acceptable answers:
Anything related to the Lean Startup
Anything related to Customer Development
Anything related to any other form of fanboy, wantrepreneur bullshit
Disclaimer: I'm not saying that these above references are bad (except maybe the last one), nor am I implying that the third is descriptive of the first two, I just think they are overused. Trying to tease out some new ideas here.
As a developer, you never know what kind of applications people need or are looking to create, but you get ideas from the projects that are posted. Most projects I'm interested in are clones with a "twist". For example, there was a request to clone zocdoc, but with a twist. There was project for rental items management software that I worked on. Another that combined invoicing and job scheduling for people such as plumbers and landscapers. Currently I'm working on a clone of elance but for a different industry. I would have known NONE of this if I weren't freelancing.