Do you hear that sound? Another deadline passing us by. When you owe money, you can actually here it whistle as it approaches... :) I found a presentation from the CRA that explains where all the revenues and expenses of the Government comes from and goes to. Some highlights for the fiscal year ending March 31st, 2007:

(Note these won't add up since I'm only presenting some highlights, see link below for more info) 

Revenues ($236 Billion Total)

$110.5 Billion - Income Tax
$37.7 Billion - Corporate Tax
$31.1 Billion - GST

Expenses

$33.9 Billion - Interest on National Debt
$30.3 Billion - Elderly Benefits (OAS, GIS, etc.)
$63.3 Billion - Operating Expenses of Government
       $6.8 Billion - Canada Revenue Agency
       $1.7 Billion - CBC (!)

Surplus - $13.8 Billion

You can view the CRA's presentation yourself by clicking here.