One year, for our ward's Christmas party, I made a model of the Salt Lake Temple out of sugar cubes. I put a strand of white Christmas lights inside to make it light up in the dark. Here are some enlarged pictures of the one I made: detailed directions to learn how to make your own sugar cube crafts!
If you make any LDS crafts out of sugar cubes please email me as I'd love to see what you've made!
Update: I'm not the only one who's made a temple out of sugar cubes! The Nov. 2004 Friend has a small blurb under the "Friends in the News" section where one primary in Connecticut put together a sugar cube model of the Nauvoo Temple. There's a small picture of the temple as well.