I used to go spinning and loathed it. I went with a friend who was considerably more overweight than I am and she loved it. I went twice a week for about 5 months before she felt confident enough to go alone. I am not sure I lost any weight doing it but it definitely gave me a good cardio workout. I needed a coffee and a large cake after spinning to get over the shock of seeing myself in a huge mirror and having to listen to awful and horrendously loud hip hop type music for 45 minutes. The music was so loud that I couldn't actually hear the instructors shouted instructions, she was miked up too. The flashing lights got on my pips too.
Interestingly, although I went spinning twice a week for 5 months with her to give her confidence, she refused to come rollerblading with me to give me confidence.