Need ideas for setting up work contest

[Betty]

I've got a fun new project: Creating a contest themed to The Amazing Race for our sales staff

It's going to be judged on their closing ratio and will run for 12 weeks.

What I want: Some sort of race I can illustrate on a map where they start in Timbuktu and make their way back to our office over the course of the contest. The contest would start with us giving them a plane "ticket" with the rules on it. I'd love to illustrate their progress as traveling through different countries and making their way back. (We'd like to through things in along the way to shake it up a bit but I haven't got that far yet.)

My first thought was to have a weekly running total. If they go on 10 appt's and sell 5 of them, their closing ratio of 50% would equal 50 points.

The problem: Our longish sales cycle means that appt's from last week may sell this week or next week - so I don't think I can have a weekly total with points. Instead, the closing ratio has to be updated weekly and kept as a ratio.

This makes it hard for me to calculate points on a weekly basis as they sell something this week for an appointment they went on last week.

The bottom line is at the end of 12 weeks, whoever has the highest closing ratio overall will win. That's the only thing I can't really change.

Does anyone have any ideas or tips on how to make this work with this theme? (I would also be open to other themes - this is what was suggested to me.)