The World Ceilidh, is the smaller of two music fests, held at a remote West Coast spot on Knockengorroch farm each year (the other is the World Ceilidh). Smaller than T In The Park, and with a strong Celtic and world roots music flavour, it has gathered a loyal following, yet still retains much of the idealism with which it was originally set-up.
It is remote though, so camping is pretty much a given unless you're a close friend of the farmer, music (and dancing in the field) is on throughout the day in several venues, and the beer is a good price and tasty (heather ale on tap last year and a fancy cocktail bar under the canvas).
There's a variety of food vendors (crepes, chips, curry), chai tents, a healing area, various jams going on, a cinema/club tent, cabaret, puppetry, kids' workshops, and storytelling. If rain is expected, which is likely at this time of year, take your wellies and don't camp too close to the river ;-)