After significant publicity and a rapidly appreciating conversion rate, Bitcoin is a widely recognized phenomenon. But to some extent it’s also still a geeky crypto-currency held by a relatively small number of people — who, at least in a recent case, have proven themselves generous to fellow enthusiasts. Yesterday, ESPN’s College Gameday picked up footage of a fan holding a sign that said “Hi Mom send Bitcoin” (using the Bitcoin symbol), then a QR code for a Bitcoin address.