There is one great social initiative in Estonia which some of my friends are actively involved in. It's called "SINA" ("YOU"). It helps active young people aged 13-19 to come up with and drive the social entrepreneurship ideas. One can become a mentor for such groups of young people.
SINA is recruiting new mentors now. Any proactive Estonian people who want to contribute their time to the work with talented teenagers are welcome to apply - more information in Estonian is on the website of the programme.