I've been tutoring a revolving group of immigrant students for free over the last year or so, but it wasn't with any outside organization or company -- I just organized the tutoring sessions privately. Would I be able to put this down for my activities? (In other words, how would they know I wasn't making things up?) Should I register my group with some nonprofit organization so we can have a more "official" standing? Thank you so much in advance, and hope you guys have a great night!