Two Muslim women, one European who converted to Islam, spoke in English to the crowd of mostly tourists and explained a bit of the religion, the culture, and the common practices within the mosque.
The cost is 10 AED (less than $3 USD) and infinitely rewarding if you are interested in understanding the religion and how it fits into modern Arab society and around the world.
Women are expected to wear a headscarf and everyone should dress respectfully conservative. I found this crowd of tourist women to be the most colorfully-covered group in the region; with scarves that were likely sourced from all over the world - and not the traditional black abaya that most Emirati women wear.
The largest mosque in Dubai and the only one open to non-Muslims, the Jumeirah Mosque dominates the upscale beach area. The cream-colored sandstone structure with two slim minarets holds some 1,200 faithful. Though it looks historic, the mosque only dates as far back as the late 1970s. An hour-long guided tour takes visitors through the pale-yellow-and-azure interior. As you admire the magnificent ceiling decorations, you'll also get a nice break from the city heat and noise.