Here's a tutorial discussing how to make piles of rubble. I use
reactor in this lesson, but below that I have some suggestions on other
ways to make rubble, and I may expand those suggestions into
mini-lessons in the future.
Rubble Using Reactor
1) First I made some simple pieces of rubble. These are all just
poly modeled boxes with a simple concrete material applied. If this was
a real production, I'd add much more detail, but these should be fine
to show off the technique. Also, make sure their pivots are in the
center of the objects.

2) I create a simple ground plane.
3) I use the clone function to place a whole bunch of the debris
objects above the ground plane (I use instance to save on memory). Make
sure none of them interpenetrate. Also, play with different positions
of the objects to get different types of piles.

4) Randomly scale and rotate the objects. To do this, I used the
transformRandomizer script available at http://www.neilblevins.com/soulburnscripts/soulburnscripts.htm.
Because their pivots are at the center, you can rotate them around
their center point using the script (just make sure "Use Pivot Point
Center" is used on your Main Toolbar).

5) Go to Create -> Helpers -> Reactor -> RBCollection and
add all your objects.
6) Select the ground plane, Go to Utilities -> Reactor ->
Properties, check unyielding and Concave Use Mesh (choose other options
if your ground plane isn't a perfectly flat plane)
7) Select your debris objects, Go to Utilities -> Reactor ->
Properties, choose a large mass, say 500 kg, and a friction of 0.9.
8) Adjust the Col Tolerance value in the World rollout. Reducing this
means objects are more accurate when they try and avoid
interpenetrating. For the size of my scene, 0.5 works well.
9) Go to the Preview & Animation rollout of Reactor, click Preview
In Window
10) In the reactor window, press Simulation -> Play. Pause it after
all the rubble comes to rest. Don't worry if some of the rubble pieces
fall off the edge. Either make your ground plane bigger, or just delete
those objects once you return to max.
11) Choose Max -> Update Max in the reactor window
12) Close the Reactor Window, now you have your pile of rubble.
13) Do a cleanup phase. Due to limitations in your Reactor settings,
you may find some of your debris is floating ever so slightly above
other debris or the ground plane, etc. A quick check for
interpenetrating will solve this, and you may need to move an object or
two to avoid any obvious overlaps.

And there you have it, a nice easy quick pile of rubble. Here's a max file you can use (max 8 format).
Other techniques to try...
1) Use the scatter compound object to place tons of debris on the
ground. Make sure to use some sort of random face selection on your
distribution object so you don't get a uniform distribution. The two
issues with this technique is objects will interpenetrate each other,
and you won't get objects piled on top of one another other.
2) Use Peter Watje's scatter utility instead of the built in max
scatter, http://www.maxplugins.de/max8.php?search=scatter&sort=Author.
The advantage of this is you have more control over distribution, and
adding multiple types of geometry. The disadvantage is it's not a
procedural object, so once you've created it, you can't easily go back
and tweak its creation parameters.
3) Pflow particle system, with it you can distribute objects based
off bitmaps, which might be useful for adding specific types of debris
in specific places over a large surface quickly.
4) Use the script called objectDropper http://www.neilblevins.com/soulburnscripts/soulburnscripts.htm.
This does a similar job to reactor, except again, it won't keep the
objects from interpenetrating, and you can't say have the pieces bounce
or slide a little once they hit the ground.
5) Use some sort of texture and displacement material to add wreckage
looking stuff on the ground for cheap.
6) Use the Advanced Painter http://www.scriptspot.com/start.asp?p=main_scripts&Sort=Name&BrowseType=Search&SearchField=advanced+painter
to paint objects on the ground.
And remember, all these techniques can be mixed together too, so you
can use the technique that's best for placing whatever sort of debris
you want to place. Like maybe do most of your small rubble using
scatter, then place a few larger hero pieces using the reactor
technique.