Registration form needs better protection against spambots

We need to increase protection against spambot registrations by a number of layers, including:

• More fake POST fields, especially similar to currently used by spambots, like URL, WWW, Age, City, Country, Sex
• Reverse agreement logic:
  <dsp2003> by altering the data which is expected by board engine
  <dsp2003> for example, reverse the flag "i agree"
  <dsp2003> to "i don't agree to the forum rules"
• Customize captcha:
  "Please post current date +/- random amount of days in RRR-MM-DD format"
  "Please post date of random commit number (from svn, viewvc or CIA)"

Any others?