A website that lets you create legit-looking GitHub links that rickroll the visitor.
Just replace github.com with microsoftgithub.com. Yup, that's all! The resulting url will redirect to the rickroll video. For example, github.com/ashmonty/website becomes microsoftgithub.com/ashmonty/website.
The link's social media preview will look exactly like the official one.
When I found this domain I decided to buy it because I didn't want it to end up in the hands of a scammer to be used as a phishing link, and it was dirt cheap. With the domain in my hands, I figured it would've been a shame not to use it to rickroll people.
How many people, you ask? 33k and counting (that's excluding bots and crawlers, btw)!