I like that game mode list Michael, but can we do all of that in 3 months now?

I think a level editor and vehicle editor could be cut out of the project to save time now, and that they can always be added after the competition.
If we get the game done in 2 months and have a month left, we can add those in then?

I would say drop multiplayer till after the competition too as a time saver.

If we concentrate on single player racing against ai controlled challengers and perhaps 3 to 4 levels that would be doable in 2 to 3 months.

Here is just some ideas:

Level 1 - Desert Map, flat terrain and easiest course, used for training and first race.
Level 2 - Curvy Course Race with Hills or Jumps this could be in a futuristic stadium or city
Level 3 - Ridge Race, the course hangs off of cliffs, there are boulders that have slid down, jumps to do and through tunnels
Level 4 - This could be very arcady, loops, lots of colors and effects as you go around the course

I am just throwing out ideas to narrow our goals down to something we could meet for the contest.

I like all the ideas that were listed but I think many could be moved to post contest to make things easier to meet deadlins.