Interslavic Language
Very interesting. I've tried to read some texts and I could easily understand them (as a native Polish speaker). I wonder if it is as easy for other Slavic  nationalities. If so, it could be a nice intermediary language, if only for written texts. Unfortunately I guess almost nobody would learn to write or speak it but it is still funny to have a passive ability to read and understand and I guess all Slavic languages could be automatically translated to this interslavic version. It could be tried in museums, restaurants, etc.