I've attended this event, or played at it, since it's beginning at the Dog and Duck pub. Now it's a large event at Fiesta Gardens, that includes the usual music and dance performances, and also historic battle recreations, sheep herding demos, a dog parade, Viking invasion, etc... here's the website so you can see for yourself:
http://www.austincelts.org/festival/
I'll be there Saturday afternoon and evening, it's a great price for the level of music they have. The headline acts are world renowned from Ireland and Scotland. Andy M. Stewart is my wife's favorite singer, and Liz Carroll is one of my all time favorite fiddlers, and I'm a fiddle player. Four stages, so there's always something going down.