Sultan Qaboos Grand Mosque is the third largest mosque in the world and mostly the entire complex is open to non-Muslim visitors every day except Thursday and Friday. The mosque includes a Swarovski crystal chandelier, the second largest hand made persian carpet in the world and amazing marble panelling.
Bait az-Zubair Museum features displays on Omani social history, while tours are frequently run of the neighbouring reconstructed townhouse. There are several other museums of interest in the capital. A number of factories are open for visitors such as the Omani halwah factory and the Amouage perfume factory. Amouage perfume is the most valuable perfume in the world.
You can also use Wadi Kabeer as a base to travel on the Sultan Qaboos Highway to Seeb, Sohar and eventually the northern most tip of Oman, where you can discover the true beauty of the Oman coast-line with clear beaches, fisherman with drag nets and open space to walk for hours. There really are so many things to do around Wadi Kabir without having to travel far.