Sorry to take so long to get back to you. MIR is Mosport International Raceway which is part of Canadian Tire Motorsport Park north of Bowmanville and is the fastest dedicated road circuit in the western hemisphere.
If you are new to track driving I would highly suggest you take a school to start with. We run ours at the Driver Development Track or DDT at the same Canadian Tire Motorsport Park. Not as fast as MIR and not as intimidating but challenging and busy with lots of elevation changes. Our 1 day school runs on May 14.
You need to have a newer (i.e.2005 or newer) Snell rated helmet either SA or M style and a car with seatbelts and brakes in good condition. A Speed 6 is fine.
The Ontario Time-Attack series is a great way to get started on the track. There is lapping in the morning divided by car/driver speeds with a dedicated Novice group with instructors available (don't get that at many lapping days). In the afternoon competition sessions there are usually 3 sessions each of 5 laps including 1 warm up lap , 3 hot laps and 1 cool down lap. There is no passing allowed in the competition sessions so the chance of car to car contact is just about zero (it has never happened yet). You are able to drive at your own pace and use the skills you learned in the morning without any fear of having other cars near you on the track. The competition aspect is pretty low key as we don't have any significant prizes, it is just for fun and bragging rights. Usually the best competition is against yourself or someone with a similar type car.
We are anticipating a big turn out for this season and the first time you can sign up for any event is April 2 at the JRP open house in Mississauga where there are also significant discounts. Prices this year are cheaper across the board and we take $CDN at par !!
Be aware that there is an entry limit for each event which varies from track to track.
Here is the schedule for the whole season
http://www.casc.on.ca/forums/showthread.php?t=32866