Thanks Baldy.
Hehe...aight sorry DownShift. I'll try to give you a better example.
Solo I (that's a "one") races are just like the touring car classes that you see on speedvision. You know, like Team RealTime and their quick little Type R's, RSX's. The biggest difference is that Solo I would be more on a regional level. Not any big-time-sponsorship-dedicated race teams.
Solo II, well since you stated that Auto-X is fun, that's exactly that. Solo II IS Autocross. You know what AutoX is so you know Solo II.
Pro-Solo. Hmmm...okay, it' still autocross. But say I have a course (course A). And it is configured like a "D." The mirror track (course B) that your competitor (or you) runs on looks just like that same "D" except mirrored. So it'd look like a backwards "D." Of course, most configurations aren't that easy.

There's also a drag race "tree," (sound familar?) to let you know when to go. Both cars race on their own course (A or B) and when that's all done, you switch courses and start over. Sound fun? See you at the tracks.