Operation Mason Relic 3 at the end of May, slight drive for you but not bad since you can "cut across" the states pretty easily, theres a post on the home page for it. 200+ players, 2 day event. There is also some gun rentals available so you do not have to risk possible border issues with your guns, just bring your gear and mags.
Saskatchewan Age Verifier! Contact for more Info.
http://airsoftcanada.com/showthread.php?t=174161 - Honour & Respect your fellow players! #Airsofthonourandrespect