How good are you at valuing websites?

Here’s a competition which might interest some of you- but hurry: only 24 hours remain!
http://www.splashpress.com/2007/worth-value/
How would you apply the techniques needed to value a website or network of sites to your own websites? Have you valued your own site? If I had the time, it would be fun to work out the estimated “value” of  all the sites Colorteck hosts!