What rules govern how I can power a Redstone Lamp?

The new Redstone Lamp is a great way to create a toggleable light source, but what rules govern how I can power it? Specifically, what are the configurations I can use to light it up? A direct line of Redstone Wire into the block is obvious, but what about adjacent blocks?

Pistons have interesting ways to power them; I'm just wondering if Redstone Lamps have equally interesting methods.

Redstone Lamps (unlike glowstone and pistons) act like opaque blocks, not transparent ones. Opaque blocks have two main differences from transparent ones:

1. They power adjacent opaque blocks when given "normal" power (like a redstone wire running into the block), and they power adjacent transparent blocks (including redstone wire and pistons) when given "hard" power (like a repeater running into the block or a torch underneath the block). They will not power any adjacent blocks when given "soft" power (like power from an adjacent redstone torch).
2. Redstone wire, redstone torches, and other objects that "attach" to blocks can be placed on redstone lamps.

This means that redstone lamps behave mostly like any other solid block in Minecraft when it comes to how they are powered, so you can power them many different ways:

That configuration on the left is powered by a redstone torch under the middle block, like so:

While having redstone lamps be opaque opens a great deal of possibilities, it also has the unfortunate downside of making it impossible (unless there's a method I'm not aware of) to turn on a single redstone lamp in a floor made out of lamps from below, so keep that in mind when building structures with them.

Picture 3 layers. On the bottom layer place one redstone torch in a 3x3 block area:

...
.R.
...

In the middle layer, which is on top of the redstone torch, place a 3x3 of dirt blocks:

DDD
DDD
DDD

On the top layer place a 3x3 block of redstone lamps:

LLL
LLL
LLL

Only one of the redstone lamps will light:

LLL
LXL
LLL