How to Pixellate an object in Illustrator.
I saw this idea on the Adobe forums, but I thought it was worth demonstrating.

Step 1.
Create Initial art and Background objects. Outline text, and use Pathfinder-Add on foreground object and background object.

Step 2.
Align forground object over background and copy background to a separate layer and lock for step 5
Step 3.
Pathfinder-Add
and Expand.
Step 4.
Direct Select letters and copy.
Remove Extra Pattern objects.
Step 5.
Place letters over copy of
background pattern and unlock the copy.
Step 6.
Pathfinder Intersect
and Expand.