I feel a need to get out of the city, and was recently recommended Kochelsee/Walchensee as a day trip destination. You can learn more at www.kochel.de.
Of particular interest to me is the Hydropower station Walchensee-Kraftwerk. If there's interest, I can see about arranging a tour.
One can get to Kochel from Munich via Deutsche Bahn. It's a bit over an hour, with one connection in Tutzing. Between Kochel and Walchensee, there is a bus. It only runs every two hours on Saturdays, however. I don't have a car, but am willing to be convinced to rent one and share the costs. My first choice would be DB, though.
I don't have much more of a plan right now other than just to head over there on Saturday and check it out, maybe hike around some. If that is too vague, however, more detailed planning can be done as well.
If you're interested, post or pm me.