Putting destrutible environs into an Arena map

[Tyrant9]

How do I put in destructible environs, at least collapsible buildings or blasting holes into walls, into an Arena Map?

[Xenogenetic]

Tie a brush to the entity func_breakable (I think thats what its called) and then you can change settings around to break it just how you want it to.

[wisecode]

This should help a bit:
http://www.sdknuts.com/tutorials/wiseCollapse.asp