Great ideas, inventions, and companies are born of providing convenience to our daily lives. It would be nice to have a database of daily tasks. It would serve as a reference point to spurn creativity.
Another way to get the mind thinking and innovating could be with a word game. A few words could be provided, and then a user could create an idea for a company from those words. I participated in a live version of this at Startup Weekend Charlotte.
Overall, both of these are for when a person wants to come up with a million-dollar-idea but can’t think of anything.
Besides a website, a mobile app could be made in a game format. It could help users build ideas through a series of questions following the initial starting point (a daily task or random words). It could guide the user into building an idea, piece by piece.
As for long term, look at Cashflow, the game based on Rich Dad, Poor Dad. This created an international community of clubs and Meetups for people interested in new ideas.