Ask HN: Small side-project with clear user tunnel?

In preparation for an incoming project next week, I'm tweaking my toolset, and implementing A/B testing (amongst other small improvements).

However, historical data suggest, that such tweaks can not happen "in vacuum" -which would inevitably lead to scope freak- but rather within the scope of a specific project which would exercise the new feature-set.

Thus, I'm offering my weekend for the community: got any fun little[1] itch you need scratched that has a clear user funnel with specific goal points? If so, share below. Best one will be implemented, and put online -it's a win-win for both of us :)

[1] The toolset is kinda extensive, what with rolling for over 8 years, so well-traversed paths (eg. registration, password remainder, etc) are almost always a 5-minute job; except for the business logic which inevitably varies from project to project. So def little = thin business logic