Stop and Go
I learned "Stop & Go" many years ago and while it isn't very difficult, it is kinda neat. Since this was one of my favourite tricks when I was younger, I figure it's my duty to illustrate it. This trick involves having the yo-yo stop spinning and with a pull here and there it starts spinning again. Another name for this trick is "Perpetual Motion."

Begin with the "Skin the Cat" position like shown.

You can also use an "Under" or "Over" mount for this trick.

Thread the string into the groove.

Bring the right hand up...

...and continue to bring it up until the right hand is level with the left hand.

Now cup your hand like so. Give the yo-yo a slight tug with both hands to cause the yo-yo to come up.

As you can see, the yo-yo is now wound up in your hands. The yo-yo is now dead, it's not sleeping anymore.

Uncup the hands and you'll be in this position. Begin to pull up with your left hand and pull down with your right. This will revive the dead yo-yo and cause to spin again.

It's very important that you do this simultaneously. Pull up and down at the same time swiftly. Remember you're trying to make it spin back up again so pull hard and fast. Pretend you're trying to start a gasoline lawn mower.

The yo-yo is now sleeping again. You can finish the trick by returning it to the hand.

Not a hard trick at all but I decided to illustrate it simply because I love it. I first saw this trick being done by Arne Dixon in one of his music videos many years ago.