Btw, I have recently started a small code battle upon an easy task.
The goal is to improve your self estimation skill and to code something minimalistic in the shortest time possible.

If you want to join the battle, just do the following:

1) Check the briefing: "Create a webservice that is generating the 'Che Guevara Effect' on an uploaded picture"
I have already done my job and implented an working version of this here: http://che-guevara-fy.heroku.com/

2) You can accept the challenge by giving an upfront estimate on how much time you think is needed to implement and deploy the briefing.

3) When working on the implementation _always_ have an time tracker running. This is for your your own good, as the better you can estimate yourself the better it is. It only works if your honest with yourself and track the exact working time from start to finish.

4) When you're done, send an link to the publicly available project of yours. It must be able to process any reasonable sized image file with the expected result to pass.

5) After that make your complete source code and hosting plan available. It will be compared and evaluated against the other implementations.

6) Last but not least, you are free to use any technology (yes, even webservices) but it must work repeatingly whenever evaluation takes place.