If you're playing hold'em and your two hole cards are of the same suit and of consecutive values you are said to have suited connectors. The value of this holding depends largely on your style of play, but if you're going to tackle big pairs they give you a fighting chance of busting those premium hands. They also have the advantage of being tough to spot until it is too late.
It helps to rememeber, however, that suited connectors are very speculative, and in many respects the ultimate example of a drawing hand. If you're holding the five and six of hearts your hand must improve drastically after the flop in order for you to have any chance of winning. A lot of poker players commit the logical fallacy of assuming that because suited connecttors play well against big hands that they are in fact big hands in their own right. Nothing could be further from the truth, as potential and actuality do not always come together as one in poker.