Aside from Heart Events with the girl you would like to wed, there are around one hundred different random events! That's a lot, right? There is no need to do them all, but if you want to it will take some work. To activate these events, many require that you have a certain amount of friendship with the villagers participating in them. Others are activated by different requirements. Aside from that, you do have to be "in the right place at the right time".
All of these events take place in nine different areas, depending on who is involved and what is happening. Some of these events are actually well known, and many players go through them. For example, the "Island Millionaire" and the "Free Horse", but others are simply so unknown and random that over half of them are a complete surprise! Good luck activating them all!