Dynamic grouping and filtering of data

Hi eveybody,

right now I have to implement a view which should allow the user to
group and filter data freely. I mean, the user should be able to freely
add and remove filters and groups. But right now, I have no clue how to
implement such a feature. Any ideas?

I know, this isn't a really extensive description, but right now I do
not know how to describe it in more detail.