How long does beer usually actively ferment?

My beer has been in the primary for about 5 days, and I still have pretty active airlock bubbling going on. It had really intense fermentation, to the point where it was spilling beer up and out of the airlock and onto the lid, and now (after cleaning the mess) it has slowed down but is still bubbling clear quite a bit.

How long does the fermentation usually go for, and is that normal? The other batches i've brewed have showed little to no bubbling before so thats why i'm surprised at the activity.

This batch is a partial mash bavarian hefeweisen by the way, and its been hovering around 68 degrees in the primary.

Thanks!

Some beers ferment mildly, some are active, others are violent.

Airlocks say little about yeast activity because post fermentative off gassing looks the same in an airlock as does mid-fermentative off gassing.

Your hydro knows the truth.