My contract is over so this will be the last installment in my high school lesson list.   Basically it's a list of ideas that never quite made it into full lessons:

Dancing
An easy vocabulary based lesson using videos from YouTube.  Depending on how broad you want to go there's Ballet, Tango, or Break Dancing (Featuring K-Kid Hong 10).  If you want to extend it there's always Cha Cha, Disco, Flamenco, Foxtrot, Jazz, Line Dancing, Mambo, Merengue, Peabody, Polka, Rumba, Salsa, Samba, Swing, Tango, Twist, Waltz, etc.  In theory this lesson should work since the kids are all about 'freestyle' and cross-dressing pantomime.[/li][/list]

My Home Country
I can't believe I never got around to this but this is an easy lesson to do if you use my Geography templates.  Another take is to turn it into a Korea vs. My Home Country.  For example, compare Canada and Korea by landmass, population, etc with visual maps.  Demonstrate how many South Koreas can fit into Canada or compare population of Seoul by drawing a circle by filling it with the population of Canadian cities.  You can even get into the concept of monocultural and multicultural societies if the class is advance enough.

Loanwords
This is from this Korea Beat article but it could be treated as an extension of the Konglish lesson.

Hyperbole
In a Korean context this would seem like an attack on the English press in Korea, but really it's an attack on bad writing everywhere.  No nation is immune from it.  As an introduction you would start out my comparatives and superlatives lesson but introduce the concepts of exaggerations.  Big, Bigger, and Biggest leads into Huge, Gigantic, Mammoth, etc.  And then if your class is smart enough, break out the Namdaemun hyperboles and explain why the writing is good for entertainment but bad for journalism.

Stereotypes
This is another advance class, largely built from what I learned in about racism and xenophobic racism post and can be split into many smaller areas.  This could be a sensitive subject so the best way is to introduce the stereotype in question and the follow up with the equivalent Korean stereotype.  For example Brian and Matt have done amazing work covering the recent example of Nazism Chic.

Anyhoo that's all I got.  On a more entertaining note I had one oddly placed day in my schedule so I came up with this extension to my sports lesson: