Thursday 23th and Friday 24th of March we are having a mini-sprint in the Ede (NL) in which we will fix CiviCRM bugs. We are with four of us already (Erik Hommel, Alain Benbassat, Klaas Eikelboom and me) so it is going to be fun! That is the main reason and the other reason is that we want to contribute to CiviCRM Core.
Our plan is to have two days for fixing CiviCRM bugs once in the month or once in the two months. But at least regularly and fitting to our busy schedule.