I once told a local muslim shopkeeper that I had always wanted to go inside a mosque. No problem he said, any friday you want just let me know and you can come with me to friday prayers. So the very next friday I went to the local mosque with him, it was a truly fascinating and brilliant experience. I spent about an hour there being shown around but what impressed me most was just how friendly and welcoming they were. The imams went out of their way to focus on what muslims and christians shared in common, rather than any differences, something which they clearly relished doing. They also constantly urged me to ask questions. All in all a tremendously worthwhile experience imo and I would urge other non-muslims to do the same.