This week all I think we need is a fitness guage.
http://en.wikipedia.org/wiki/Multi-stage_fitness_test

Read up on how it works and make note of what profession you're able to qaulify for, highest being the Royal Marines with a minimum entry score of 11.3. If you're able to reach level 10 already then you could potentially run the half tomorrow if you wanted and will only require some pacing practice to see how you react over long distances.

So find a good beep test mp3, preferrably one with warning beeps to aid your pacing, and throw it on your device. Head down to a park or basketball court, find 20m and give it a whirl. No eating 2 hours beforehand!