Depending on how active you're feeling you can hire either a pedalo or a row boat for thirty minutes or an hour, vigorously exploring the circumference of the lake's picturesque islands, or simply kicking back and drifting wherever the water wants to take you.
Having no upper-body strength I opted for the pedalo. This option has the added advantage that you can sneakily stop pedalling any time and let the other sailor do the hard work while you relax and watch the world go by.
The landscape surrounding the boating lake is very scenic and peaceful and, with space for five in a boat, the whole family can enjoy adventure on the high seas for a reasonable price.
You won't need to worry about sinking (although efficient lifeguards are standing by and life jackets are provided for children under 12 just in case) but there is a chance of taking on a bit of water so I'd advise taking your shoes off if you don't want them getting damp.
The pedalo is good exercise if you actually do some pedalling, but never fear, there's a convenient café next to the boating lake, and ice cream outside, where you can pile all the calories back on.
There is also a little pedal boat pond for little people. The opening hours for the pond are the same as for the lake and although I'm a bit too large to try it out, the squeals of joy can be heard from well out of sight, which is enough evidence of a good time for me.
Safety note: Pedalos aren't the same as dodgems...