MUC (Mono-Blue Control) is one of the oldest running archetypes in Legacy, and even the history of Magic. Blue has a lot of strengths, but undeniably it's largest are drawing cards and countering spells. The deck is built around a simple game plan: Counter everything your opponents play, and draw lots of cards so you have more counters than they have spells. Once you establish total control, you will drop a way to close out the game. There is a variety of ways to do this, but the most common nowadays is easily playing Jace, the Mind Sculptor.
The deck saw little play for years, but with the printing of Mental Misstep in New Phyrexia players like Gerry Thompson have given the deck a resurgence in terms of popularity.
MUC - SCG.com Legacy Open Louisville