It is a new year again, please remember that your returns for 2011 should be filed on or before April 30, 2012.
Filings done after this date may cause delays on your GST/HST credit (including any related provincial credit), Canada Child Tax Benefit payments (including those from certain related provincial or territorial programs), and Old Age Security benefit payments.
Reference: http://www.cra-arc.gc.ca/tx/ndvdls/tpcs/ll-dts/frms-eng.html