For real, though.
I have a PHP-based ActivityPub (micro)blogging service and platform I have begun work on. It is extremely early stages, because I do not have a high rate of code output, but I DO have good project organizational skills and structural design.
If you have interest or experience in PHP, CSS, or Regular Javascript and want to help make a modular, extensible alternative to Mastodon, hit me up. I would be happy to discuss my ideas and hear yours.