A lock screen feature on PCs, smartphones, tablets, etc. that displays an image representing a certain problem (like cover images of brainstorming sessions on this platform) and a line of text inviting to solve it. Clicking on a text leads you to the page dedicated to that problem on an online ideation platform. Each time you are locked out of your device you see a different image with a different problem to solve. Some problems on a platform have rewards (monetary or other) offered for solving them.
A way to get many people interested in problem-solving.
Be entertained with an opportunity for being productive and useful (solution to this problem).
Help other people solve problems.
Make money/gain rewards.
If the user got interested seeing the problem displayed on the lock screen, after clicking on the link they'd be taken to an online page dedicated to solving that particular problem where they'd see solutions suggested by other people and could offer their own. The lock screen could instantly (before clicking on the link) display if there's a reward attached to the problem, how many people have already contributed, is there a deadline for solving it, etc.
The problem-solving platform could cooperate with major software producers (Windows, Apple, Android, etc.) and pay them a certain percentage from the benefits they get. The users could regulate the function through the device's settings - turn the invitations to solve problems off, request to see only the problems with attached rewards, etc.
Windows 10 has an interesting lock screen function, it shows you different landscapes around the world with a related quiz question attached to each like a riddle, when you click on the question it takes you to the webpage with different answer options you can choose from with a Wikipedia page of that topic displayed on the side. There's a different landscape/question every time you are about to log in to windows. It keeps you interested and I have to confess I follow the question links quite often.
This got me thinking that the quiz questions could be replaced by invitations to solve interesting problems and landscape images with pictures illustrating the problem. Also, this is a related idea.