The Pembina Valley, starting south of Morden (take the 432 south at the west end of town until you hook up with the 201) and going West for many many miles. Lots of trails, hills, scenery, etc. You might want to check out
Hy-Wire Zipline Adventures
whilst you're in the area and make a wknd out of it.
If you take the 201 hwy starting just south of Morden, this opens up a nice ride all the way out to hwy 34 going West just above the US border. From it you can branch off to all sorts of great trails, etc. The trails range from packed dirt roads to downright "real" dirtbike-type riding conditions.
Pembina Valley Provincial Park has some great trails (although legally only for hiking...) but lots of back roads/trails/hills for riding. http://www.rmofpembina.com/pvpp.htm
I generally keep a few extra Keiths on hand as well for any visiting Strommers.....
K5Wee in Kanada (255,500 KM and stalled for winter)
IF YOU WON'T STAND BEHIND OUR TROOPS.....FEEL FREE TO STAND IN FRONT OF THEM