And if you really feel ambitious then you might try creating a special profile just for when you go to bed, then it will not notify you... the only problem is you have to remember to change your profile before you go to bed every night.
This is one of the reasons I love BerryBuzz... all my email notifications are set to Mute on specific Profiles... it just set to give me a blinking light color of my choice for every email address... this way it never makes any noise unless I want it to.