Hard one to answer without knowing what the idea is. Taking the example of people learning a language: For argument same I will assume ESL (English as second l

Hard one to answer without knowing what the idea is. Taking the example of people learning a language: For argument same I will assume ESL (English as second language). You could visit subreddits for ESL? Local ESL classes? Then Google the fuck out of ESL and related phrases for other hangouts, blogs and so on. When you read the subreddits you get more hangout ideas and so on.