Hit Test bounce - actionscript-3

Question

I'm trying to make sort of a Balloon fight game for flash. I have a ceiling at the top of the screen, so when the player hits it, it should bounce off of it. Problem is, I don't know how to go about doing that. Here is the code.
I was messing around with numbers. In the upBumping variable, where the problem lies, I wanted to have the character bounce down once it hits, but it only does this once. After, it just goes through the ceiling. Perhaps I'm going about this the wrong way?
//gravity and stuff
var gravity:Number = 0.3;
var fall:Number = 0.3;
var downBumping:Boolean = false;
var upBumping:Boolean = false;
//direction I guess
var leftKeyDown:Boolean = false;
var upKeyDown:Boolean = false;
var rightKeyDown:Boolean = false;
var spaceKeyDown:Boolean = false;
//character movement ya'll
var mainSpeed:Number = 6;
stage.addEventListener(Event.ENTER_FRAME, game);
stage.addEventListener(KeyboardEvent.KEY_DOWN, keyDownHandler);
stage.addEventListener(KeyboardEvent.KEY_UP, keyUpHandler);
function game(e:Event): void{
//if certain keys are down then move dat fool
if(leftKeyDown){
Monkey.x -= mainSpeed;
}
if(rightKeyDown){
Monkey.x += mainSpeed;
}
if(upKeyDown){
fall = fall-0.9;
gravity = 0.3;
}
if(Floor.hitTestObject(Monkey)){
downBumping = true;
trace("downBumping");
}
if(Ceiling.hitTestObject(Monkey)){
upBumping = true;
trace("upBumping");
trace(Monkey.y);
}
if(upBumping){
Monkey.y += 20;
}
Monkey.y = Monkey.y+fall;
gravity = gravity*1.0;
fall = fall+gravity;
}

Answer 1

Here's how I would do jumping and bouncing - this does not include other code like moving left to right since you already got that
function game(e:Event):void {
if(jumping){
yVelocity += 0.1; //gravity
Monkey.y += yVelocity;
if(Floor.hitTestObject(Monkey)){
jumping = false;
while(Floor.hitTestObject(Monkey)){
y--;
}
}
if(Ceiling.hitTestObject(Monkey)){
yVelocity = 0;
while(Ceiling.hitTestObject(Monkey)){
y++;
}
}
}
if(upKeyDown && !jumping){
jumping = true;
yVelocity = -3;
}
}
Obviously, declare the variables used in this example.