Failure usually isn't something you want to broadcast to the world (or at least to the two or three people who might read this blog), but sometimes doing thins badly can have interesting results. Most of my plant introductions have resulted in at least a few plants that either get dislodged, or were never actually planted. These end up floating at the top until either you re-plant them, or scoop them out. But if you're like me, sometimes you choose neither option. As a result, one end of my tank supports a fairly large mass of floating plants - a mixture of Rotala, Lilaeopsis with some Ludwigia and who knows what else mixed in. It is anchored by the top of my tallest Hygrophila difformis plant.
The interesting thing about this set-up is that it brings corys right up to the surface. While they will swim up and down my Cabomba plants (which reach the surface of the tank as well), they don't spend much time on any particular plant. On the other hand, if they make it up to the floating mat, they can spend a good bit of time exploring it. Since the interior is too dense for any of my fish to get into, it's likely to provide predator-free space for small inverts. Since my tank is deficient in fish that use the upper portions of the tank, it's nice to see the corys active near the surface.