Sansevieria

Sansevieria trifasciata (German: Bogenhanf) is a nice green plant that grows easily and doesn't need much water or light. It comes in several variants, a tall, slender one (see picture on the right), and one of short stature (called the variety "Hahnii", see below). Different leaf color schemes exist, though the ones with a yellow border around the leaves cannot be propagated: the children will always have plain green leaves.

Sansevieria can be a bit delicate when she's young, then she will not make any new sprouts and grow only from one rosetta. But Once she has decided she likes her environment, she can develop a rank root system! You can influence this by choosing where you pour the water: if you pour from the top, inside the rosettas, more leaves are formed, and if you pour from below, into the saucer, more roots grow. But somehow or other, you will need to re-pot your darling...

Now for the propagation. With the tall variant, you can cut a leaf into pieces, each about 8 cm (3 inches) long. Leave these to dry, a week or 10 weeks, it doesn't matter. But remember which end of the piece was at the top and which pointed towards the bottom. Then, simply put the pieces into some soil so they stick out with the top half (be sure to get the direction right). Water regularly, but make sure the soil is not too wet. Several months later, a new shoot will emerge from the soil – and there is your new plant!
With variety Hahnii, the shorter one, the same technique can be applied, only with the limitation that one leaf doesn't give so many pieces.

Another possibility is to separate one rosetta from the main plant. This is easily done while re-potting - it may also help to increase the average lifetime of your pots if you remove the outer rosettas - when Sansevieria decides she needs more space for further expansion, she may not feel inclined to respect such things as the pot she's growing in and she may just grow right through it (sorry, no picture available, but I have seen it, you can believe me, and I try to prevent a repetition).
Just break away some of the outer rosettas, together with some smaller roots to guarantee the nutrient supply for the child. You probably need to break one of the bigger roots where the shoot is attached to the main plant. Then put the child into its own pot - finished!