Well, nothing like Marxism has ever been tried. Leninism has little similarity to Marxism. But socialism has been tried in various forms. The more anarchistic varieties, Revolutionary Catalonia, the EZLN, and modern Rojava were/are interesting expiriments. Social democracy in Sweden and Norway, though not full socialism (which is their greatest fault), is quite interesting too. Personally, I think the Lange-Lerner model (cf. Oskar Lange and Abba Lerner), the RICH economy (cf. Robert Anton Wilson), and FALC (cf. Aaron Bastani) are the most promising socialist models. Although, I do really appreciate Murray Bookchin and Abdullah Öcalan too.