For a project, we're using the Tasking Manager to coordinate things. Thankfully it has an API (since it's just a JS front-end), so I can write something against that to display the data in ways I'd like. But the API is very specifically designed for their current frontend, so it needs a lot of hacks
When we mapped all the townlands in Ireland, I made townlands.ie, and calculated how fast people were mapping, and how long it would take to finish at that rate. It certainly motived people to keep mapping!