Loop Cut

Loop Cut = Ctrl + R or Mesh > Edge > Loop Subdivide.

* If you roll mouse wheel before you set edge loop position, you can define how many loops will be applied. Hitting numbers like 4 or 55 will also define loop numbers.
* Pressing S before first click will set Smooth cutting.
* If you set single edge loop, you can slide edge loop after first click. You can also set percentage value between -1 to 1.