Here is a quick tutorial that I wrote a while back...
What You Should Already Know:
I'll assume you already know how to make a mover that is set up with a trigger.
The Tutorial:
This can range from exploding cretes, doors, walls, glass and so on. This particular tutorial will cover a basic exploding air vent cover.
Once you've created your level you will want to create the exploding air vent. First make the mover then set it in your level where the air vent will be. Set its Keyframe to 1 once in place then set its keyframe to 0 somewhere outside of your level. Now add an 'exploding wall' effect next to your mover. (found under Classes->Effects->Exploding Wall)
Then set the properties of each to the following:
Mover Properties:
Event-> Event = ExplodingWall_1
Mover-> bDamageTriggered = True
bTriggerOnlyOnce = False
DamageThreshhold = 10.00000
MoveTime = 0
StayOpenTime = 45
Object-> InitialState=TriggerOpenTimed
ExplodingWall Properties:
Advanced-> bNoDelete = True
Collision-> bCollideActors = False
bCollideWorld = False
bProjTarget = True
Events=> Tag = ExplodingWall_1
Now rebuild your level and enjoy
<BLOCKQUOTE><font size="1" face="Tahoma, Arial, Helvetica">quote:</font><HR>"Fighting for peace is like screwing for virginity"<HR></BLOCKQUOTE>