As with Answer #2, you can create a base mesh or curve, either way you will have multiple vertices which in some ways will be important, but try to keep the poly count as low as possible. When in Edit Mode, select any random vertex except for your origin and end points, press [CTRL][H] to place a "hook" to your selected vertex point, selecting the option to link to a new object; repeat for as many hooks as you may desire.
Exit Edit Mod, select ALL of your new Empties and press [CTRL][I] to insert a new keyframe at the start of your lightning animation.
Now, change the screen mode to Animation.
In animation mode, first go to the Dope Sheet in the upper right hand corner (assuming you have the standard layout) and press [A] a couple of times to deselect and then selecting all of the markers. Then press [V] to bring up the handle type menu and change all of the handle types to Vector. This will enable sharp movement of your animation curves.
You will notice that the curve I created has a bit of mass to it, I changed the extrusion a little earlier only to make the line a bit more visible here.
In the 3D window, select a single empty hooked to your mesh or curve.
Below will be a list of points where you may select actions you can perform on the X / Y / Z axis. At this point, look for the orientation of your lightning along whichever axis. Select the corresponding axis on the Graph Editor. You may have to expand out the items from the arrows to get the shot I have shown you.
Press [M] on the keyboard to bring up the left side window and select from it the Modifiers tab. Select Add Modifier and Noise. Adjust the settings to your preference. Repeat on the axis perpendicular to your lightning path.
With all of this said, you will have to model your forks in the mesh or curve yourself, but this will most definitely work to animate that lightning. You can use the same concept to animate the forks as well and give them a more drastic noise level to accomplish the effect.