Wellness Summer in Cologne?

Hi all,
I've had to cancel my summer vacation due to too much work coming my way :-(
So, I'm wondering if any of you in a similar situation would like to consider little mini-breaks locally.
I will miss the beach this year, but if you think about it, there is nothing more relaxing than spending a sunny afternoon at the wellness spa - Mediterana - in Bensberg.
Any other ideas?
Warmest,
Andy