One my favorite targets for me and for star parties is the optical pair Alcor & Mizar and Mizar is also a binary system itself which is apparent through pretty much any telescope.
In reality each of the stars in the Mizar pair is a binary making the whole telescopic view a total of 6 stars when you include the star that also shows up in the field-of-view.
Recently astronomers at the Palomar observatory were looking for extra-solar planets using near-infrared techniques and discovered that Alcor also is a binary system! That makes a total of 7 stars when you look at that one spot in the Big Dipper. Read more over at SkyandTelescope.com