The way you can contribute to bitcoin will depend on the country you are in. In some countries, trying to contribute to bitcoin by running open promotions like hosting conferences or meet-ups can be illegal and by doing so even though you are unaware, you put yourself at risk.
Even you live in a country where Bitcoin is illegal, hosting a conference or meet up about Bitcoin shouldn't be illegal. It's because you're only want to have a conversation or teach about Bitcoin, not necessary invite people to buy Bitcoin or to own it. As long as you're not encouraging people to buy Bitcoin, technically it's legal.
Education isn't a crime.