I did this lesson in 1.5 hrs class this summer since I only have a few classes before vacation. It could easily be expanded upon and made in to a camp idea depending how far and creative you'd like students to go with it so feel free.
The worksheet format is similar to my Mr. Bean post because I've had so little time to search and use a different template. Basically, I first brainstorm Korean festivals with the class and write ideas on the board. Then I show them some of my personal photos from Korean festivals I've been to as example ideas (you can insert your own festivals and photos in the slideshow) before handing out the worksheet and going over the questions and any difficult language.
I thought if I'd had more time and classes this summer I could have had them make an advertisement for it somehow and make posters with images and descriptions, whatever students wanted to do, in order to present their festival idea to the class.

I love the idea for this lesson!  Unfortunately I've yet to attend any festivals but with the miracle of google and flickr I'm sure I can find some pictures haha.  I'm totally using this.

I did a Festival lesson on Canada a few weeks ago and it worked quite well. I showed some clips of some of the famous festivals in Canada, explained why they were special and when it takes place, etc. The students were asked to get into their groups to make a poster of a .ppt about another country and its famous festivals and they had to do a presentation on it. They were a bit shy but since it was in groups and I was marking them, they were more obligated to talk.

AHHH WHAT A GREAT AND EASY LESSON PLAN ON FESTIVALS. I PREPARED A LESSON ON FESTIVALS IN BRAZIL FOR NEXT WEEK. I BATTLED A LOT. I AM VERY GLAD I CAME ACROSS THIS LESSON PLAN, I THINK I MIGHT JUST USE YOURS OR I'LL ADAPT MINE HAHA.  THANKS SO MUCK . WHAT A HELPFUL SITE!!!!!!!!!