We didn't go to one of the mosques, but to a local community centre where the Tanzanians meet and pray. The sermon (khutbah) was in Swahili (we think!) and then Arabic and all the prayers were in Arabic. My friend had lent me a small book explaining the main praying part (the salah) so that I'd have some idea of what was going on.
The quiet, polite listening from about 45, mainly African guys sat around on the floor was in itself a display of peaceful, reverential devotion.
The actual communal praying was the most interesting part. The chaps all lined up facing the same direction (in this case, due to location, the corner of a room). The stood toe-to-toe, and just about shoulder-to-shoulder with each other. (As my friend said later, "brother-to-brother").
Then in almost synchronous union, move to the kneeling/kneeling whilst bending forward poses we associate with Muslims praying. This level of communion or oneness across peoples from many corners of the globe and social classes was as good, if not better than in the best churches.
Some men arrived early and some stayed later to perform extra prayers. It would be nice to see a similar level of devotion and religiosity amongst Christian men!
All-in-all it was an enlightening, calm and reflective experience. We all believe in the same one God, we just perceive the truth in slightly different ways.