I used to be part of original son240sx.ca 8+ years ago... in it's early years. I even ran the club for a short period of time. We used to organize meets, track days etc around the GTA. Looks like they changed thier domain name to .org and they are still using the original logo one of the members designed.
There is also a local 240 club in Ottawa, Ont: neo240sx.ca
Not sure of any other 240 specific clubs in Canada, but there are several dedicated Z clubs.
BTW, my sig says 240SX but I don't own one anymore. My Nissan Rogue is my daily driver.