Some really cheap Vegas flights ....
Calgary to Las Vegas - $237 USD
Wednesday -> Saturday: Dec 9-12, Dec 16-19 ($248)
One week: Dec 9-15, Jan 5-12, Jan 12-19, Jan 19-26, Jan 26-Feb 2, Feb 2-9
Lots of other date combos available, mostly in Jan/Feb. The cheap ones are usually Sunday through Wednesday.
Check
http://www.westjet.com and look for the $79 each way (+tax) fares.
cM