Depends a bit on if you have a rental car as these are beyond public transit. If you do get a rental I'm sure the Motorsport Club of Ottawa has an autocross in May, that is if the Senators don't make it very far
http://www.capitalcityspeedway.ca/schedule%20.htm
http://www.calabogiemotorsports.com/component/option,com_jcalpro/Itemid,43/extmode,cal/date,2008-05-01/lang,en/