Although I am not a churchgoer, I’m a big fan of interesting church architecture (and there is a lot of it out there).
For example, The Hallgrímskirkja Church in Iceland:

At first I couldn’t quite remember what it reminded me of…then I realized it was the Ivory Tower in The Neverending Story
:

The Ružica Church is a small chapel in Serbia decorated with spent bullet casing, swords, and cannon parts:

The church occupies space used by the Turks as gunpowder storage for over 100 years and it had to be largely rebuilt in 1920 after WWI. While fighting alongside England and the US, Serbian soldiers on the Thessaloniki front took the time to put together these amazing chandeliers.
I’ll follow that with St. Joseph the Betrothed Greek-Catholic church, which to me resembles giant bullets:

Built in 1956, it is most known for its ultra-modern thirteen gold domed roof symbolizing the twelve apostles and Jesus Christ as the largest center dome.
The Catedral Metropolitana Nossa Senhora Aparecida in the capital of Brazil is an expression of the architect Oscar Niemeyer.

I’d love to sit in this church, if for no other reason than the feeling that I might…at any given moment…be sucked through the ceiling into some kind of heavenly vortex.
Yes, yes, we’ve all seen Russia’s St. Basil’s Cathedral, but let’s give credit where credit is due. It’s really a stunning structure:

I couldn’t possibly cover a decent sample of the interesting churches out there, but if one stands out in your mind I’d love to see a link to it.
Thanks so much to Odee for these wonderful examples (find more over there).