Is it also possible to ask questions where you can register for example workshops? It is important that with each response the available numbers of available places counts back. I do not know which question type I should use and which difinities I should use.

There is nothing out of the box.

You can use "quota", but you can't access the quota details from within a survey. If you set the quota to e.g. 300, then the person 301 that wants to enter the questionnaire will be 'screened out'.

You can't read the number of the quota into your survey, if this is what you want.

Limesurvey is not made for the registration of events. I think there are other tools out there that are developed for just this purpose and probably fit your need better.

JHakvoort wrote: It is important that with each response the available numbers of available places counts back.

If you have the time and the resources to evaluate other opensource projects, take a look at these ones (based on Drupal):
www.drupal.org/project/rng
www.drupal.org/project/webform

Thanks all.