Temple of Small Gods
The Temple of Small Gods in Ankh-Morpork is actually an important landmark, quite a large temple that sometimes serves as a meeting hall for the priests and priestesses of all the gods without enough believers to support a Temple of their own (see The Last Hero)." Small Gods" is the default church for many in Ankh-Morpork who have no real religious affiliation, but may feel the need of an appropriate place for a wedding, funeral, or other ceremony. City Watch funerals tend to be held there, with burials in the Small Gods' Cemetery (ironically the Omnians would probably be buried somewhere else).
The Temple, surmounted by its huge dome, is also a popular challenge for edificeers, who over the years have left thousands of sets of initials etched into the metal.
The ceiling was originally painted by Angelino Tweebsly, who was the famed artist who did the original mural inside the dome. This Herculanean task took him twenty years. By inference this was several hundred years before the consensus present - the power of Hughnon Ridcully's voice causes flakes and shreds of paint to drop off and fall on the congregation. As the god Blind Io points out when considering a suitable punishment for the rash impiety of Leonard of Quirm, by the time of The Last Hero the decoration is in a terrible state. Commanded by his Gods to repair, renovate and generally make good, Leonard finishes the work in three days flat (a nice symbolic number, in religious terms).