"great to hear there are old time bands in Denmark, how lively is the scene there?
Are there festivals, venues?"

The scene is very limited. We are only few bands playing that kind of music. There are about 2000 people in square dance clubs, but the number of bands who actually play that kind of music is rather small. You can find a couple of bands among our top friends in the MySpace profile mentioned above.
Possum Whackers and The Barking Bulldogs and Big Hungry Joe

Once a year, the Danish Folkmusic Society, DAFF
have a gathering in september. A weekend with dancers and musicians from all over the country gather to play, dance, jam, drink beer and have a good time.
There's is a folk music festival in Tönder, with many kinds of folkmusic. Danish, irish, scottish, scandinavian and american folk music. And once a year a bluegrass festival in Fredericia. That's about it.

"Did most old-time music originate as fiddle tunes? Invariably, at sessions I attend, fiddle players will be the first ones to call for an old-time song."

My own entrance to Old-time music, started in the early sixties, when the american folk revival hit Denmark. Dylan, Joan Baez, Pete and Mike Seeger, Woody Guthrie, Phil Ochs, Tom Paxton, inspired me to check out, the older stuff. And as mainly a guitarist and singer, became very interested in folks like Doc Watson, Clarence White, and many, many more.
Later I began to listen to bluegrass, and I admit, I am a sucker for the virtous players, like Doc, Tony Rice, Norman Blake.
And I found through the years, that a lot of the same songs and tunes could be found in both genres.
And now yet more years later, when I started playing in the band Big Hungry Joe, I find the same songs and tunes again, and learn, that it is called Old-time music.
But the basis is the same (New tunes are written off course, which only goes to show, that it is not museum music, but folk music very much alive).
If you go back and investigate the music gathered in the early and mid 60's by Folkway Smithsonian among others, you'll find, that Old-time music, found in the Appalachians, Kentucky, north Carolina, Virginia and surrounding areas, are a lot of different things.
It is a cappella songs, songs with solo banjo (mostly clawhammer or frailing), fiddle, guitar, mountain dulcimer, harmonica ("The poor man's fiddle") autoharp, bones,
jews harp.
So Old time music is a lot of other things, than just the fiddle/banjo/yeehaw/saturday night barn dance thing.
But with that said, a very central thing in OT is the fiddle and the banjo, as it is music made for dance. The pattern in the instrumentals is almost always the same: An A-part repeated two times, and a B-part repeated two times, and over again as many times as it takes to do the dance.
I think, that the "meditative" aspect mentioned above is very adequate.

But in the beginning was the song, and later the instruments came. The immigrants from mostly the british isles, came to these parts of America. As in Denmark, where I live, the fiddle was the main instrument, when there were dances out in the countryside.
Not everybody could play the fiddle, so what to do if you wanted music?
Songs! Songs were everywhere. Everybody could sing a song (this was before television and radio), and the lyrics often contained a story, that came from real life, and thus carried stories and folktales on to the next generations. This has been general for folk music everywhere I guess.

In the case of OT music, the fiddle came wih the immigrants from Europe, and in America it got into a happy marriage with the banjo that came with the black slaves from the south.
So, as someone mentioned above, it is a strong mix, between the folksongs and tunes
from europe, some of which goes back a couple of hundred years, and the influence from the black music, and the blues. And the fiddle and the banjo, is almost a lable on this kind of music.
If you try to chase some of the jug bands, and black stringbands from the 20's and 30's you will find that there's a thin line between the white bands and the black bands, they both took elements from each other. And inspired each other. So in music, so much for segregation :-)

If you have read so far, I thank you for your patience, and hope it makes some sense.