Area dice game

You'll need:

2 different colour pens/pencils
A sheet of graph paper
2 dice
A willing participant
Competitive rules:

Split the graph paper in two equal parts by drawing a line in the middle.
This line creates territory!
Each player takes it in turn to roll the two dice. 
A bit like tetris, the player draws a rectangle or square that has dimensions of the numbers shown in their own territory.
The player who crosses over into the oppositions territory first loses the game!

Cooperative rules:

Each player takes it in turn to roll two dice. 
You get 5 rolls each, and your aim is to build the tallest tower that you possibly can. 

Extension: multiply the dice to get the area first. Draw ANY regular shape of your choice with that area - using only whole, half, and quarter squares. Be creative for extra points and kudos. Would it be possible to draw a 10 sided shape with only whole, half, and quarter sqaures?