For now, anyone who's struggling with the events:
Input Event: this is what triggers the event to happen. For example, onActivate means that clicking the brick will cause the event to occur.
Target: the target is what the event will affect. Self is the brick with the event, player is the player that triggers it (in onActivate or such), etc.
Output Event: this is the event that happens. Most of them are self-explanitory, like setVelocity or playSound. If you don't understand one, try it out.
Output Parameters: these are extra things needed for some events, such as the sound playSound uses, or the direction/power setVelocity uses.
Someone wanna expand on this and start the wiki? Feel free.