This is SVG that shows the Phase of the current moon in real time! If you add it to your Github profile, web page, you can see the changing months every day. You can also make a moon phase of a specific date,

"Hide your link behind a simple quiz"
Simple service that adds a quiz ahead the link so that users can access the link only when the answer is correct

I hope my idea will help you. I'll use it for my wedding invitation.