Basically the first would be an event that would automatically stop all or a selected sound on a client, whichever's more doable. Better yet would be an event to set a loop of music to the client, using basically, as I understand, the same methods as the setMusic event for bricks. If it's possible, it'd be handy for them to be usable as minigame events as well as client events.
I myself think that the setMusic event would be both more useful and easier to make/possible to make, but I'll leave that up to the professionals.
Any volunteers?