The picture was taken at the Frankenwald Radmarathon, which is an open cycling event with several different distance courses to ride. It's not a race, though some semi-pro cyclists use it as a training event. You pay a little fee and then you get starting numbers that you are supposed to fix to your handlebars (the small numbers) and to your own back. In our case, this needs a little adaptation: we fix the small numbers to the front pedals and the back numbers to Frieder's back and the back of the saddle, and then we're good to go.
It is basically an organised long tour where you get food stops along the way (necessary to re-fuel) and a lot of other people ride along with you on the same roads, all having fun and all pedaling hard. The several times we did the FRM, we were one of the few tandems going on this ride, and with our special kind of tandem the extra-odd one out - most of the participants ride normal single road bikes.
The FRM was skipped last year and this year due to construction works that were very much in the way of the usual course, but we hope there'll be another chance to do it in the future. It's exhausting, but a real lot of fun as well!