You’ve read about it, you’ve seen it on TV, and, admit it, you’re fascinated by it. You can’t afford it, of course, and you’re skeptical of its practicality, but don’t you want to ride it? It’s the Segway Human Transporter – the invention formerly known as Ginger – and it will be at the Museum of Science Saturday, available for five-minute rides. Dean Kamen, the Manchester, N.H., inventor of Segway Human Transporter, will bring a small crew and two or three Segways. From 1 to 3p.m., those 15 and older can try it out in the Blue Wing’s Exhibit Hall. From 3 to 4p.m., Kamen will talk about the engineering of, and vision for, the HT. There’s no extra charge for the event, but there is an $11 fee to enter the museum.