For my second year high school girls, I am trying to design lessons that will go over two class periods (I see each class twice a week, for about 85 minutes total), and so far have done some successful "themes": Spring/Poetry (done right at the beginning of the year), and Superstitions (which I am still working on now). Hopefully someone else in the same boat can make use of this...

Spring/Poetry

1st Class: Show students Springtime PPT. Start by having them guess where the picture on the first slide was taken (Pohang), and poll them on their favorite seasons, then on the second slide throw around a ball and make them ask each other their favorite part about spring. Then, go over the spring vocabulary. Introduce the spring acrostic poem activity to them, and get them hyped up about a contest, giving them some time to start. 
2nd Class: Do the vocabulary review part of the Springtime PPT, making students explain definitions in English. Then give the students time to finish up their acrostic poems in class. If they are having difficulty, have the class generate a list of potential spring related words on the blackboard.

Week 2
Class 1: Show students Spring Poetry PPT. Congratulate winners of the poetry competition. Go over poem vocabulary with them, making sure to give lots of examples of rhymes and syllables, and make them guess how many syllables various English words have (my students got really into this). Then give them the Spring Rhymes worksheet (this worksheet I got directly from bogglesworldesl.com) and have them work in teams to answer the riddles.
 
Class 2: Show students time lapse video of flowers blooming, and have them describe in English what is going on. Briefly review vocabulary from last class, and then go into the Rhymes game activity.