I have been feeling like a really lame parent because I haven't been able to teach my kids how to ride a bike. But finally, they did it. Torsten somehow got over his fear of trying and basically hopped on the bike and started riding. Simon is unusually uncoordinated and it took him more time to get it, but after his brother started riding, he had more of an incentive to keep trying after each fall. And there were a lot of falls. But now they are enjoying some time outside riding bikes, which may make my no-TV-on-school-days rule less painful (for them and me).