The Riffle Pass
Here is the classic Riffle pass. Remember to practice with just your left hand in pivoting the bottom stack in and out as much as you can to begin with. Then start including your right hand to pivot the top stack up while you pivot the bottom stack with your left hand. The riffle is pretty important, it will disguise any noise you make. Also, more often than not there will be a glimpse of something going on when you perform this move. The more you practice, the shorter that glimpse will be, but the fact of the matter is that when you are playing in a card game and everyone begins drinking and chatting, no one should be staring directly at your hands as you deal, if they are, yo have done something to make people suspicious of you. Also, if the glimpse is small enough, people won't know what they saw, and may even convince themselves that they didn't see anything after all. Remember, no extra attention to yourself, don't do any flourishes, don't use too much of the jargon, keep yourself under the radar. This is a pretty risky move, but it has some awesome benefits. So don't use it too often, just when it counts.
Also, the more relaxed your hands are when you do this, the quicker your fingers will move. Tense fingers are slow.