All of Mike's suggestions are good ones, but I wouldn't try a slow roll with an LT-40 - they do them Slow enough

Another good excersize is to do a side slip on landing.

Start high (Really high at first) and make a landing approach (But do it too high, you're not going to land, just practice lining up)

As you turn to Final, just before the turn is complete, Feed in opposite rudder.

Now, at this point, all planes will react differently, so exactly what control inputs you will need will depend on your plane - but basically what you are shooting for is for the plane to freeze it's banked position (You may need to incease aileron input) and the plane will slide somewhat sideways down the glide slope.

With airplanes like trainers, Cubs, and the like, it is a really impressive looking maneuver and a great way to drop altitude without gaining a lot of unwanted speed.