Yeah, Jessen100, welcome to the new forum. Hopefully, you'll get your work firewall problem sorted soon. I know the pains of having your hands tied...I moved prefectures because something similar happened to me.
Anyways, what you're teacher at school said is correct, "fun" is of the utmost concern. However, the students are secondary...YOU need to be having fun. If it was up to a lot of Japanese ES teachers, students English classes would most likely be filled with three most overused games in Japan: Fruit Baskets, Karuta and Bingo.
The ES English plan MEXT is introducing in 2011, the top two priorities are 1.) internationalization and 2.) keeping the English class fun. I would think learning English would be the most important (

) but the moment 'English' is the goal ES teachers need to have licenses and in my experience in Japan, many teachers probably wouldn't pass those tests.
One of the stupidest things I've ever heard is, "ES 'English' classes need to be fun." WHY?!?! Like Crustpunker said, no other subject in school is bound by that requirement so why should Engl...internationalization class?!?! Speaking of which, how much is one ALT internationalized anyways? Most of us ALTs have backgrounds from only our home country. I would dare argue this is by no means makes us stuarts of internationalization. Now, put us all in the same room, that's a different story... I think what it comes down to is this: by MEXT not including 'English acquistion' as the main goal, I think demonstrates their lack of taking English classes serious.
Enough ranting...
Anyways, one of the most fun and popular English activities in ES for years with my students was the
Eto game. It practices the alphabet but it takes the emphasis off of knowing the letters and shifts to remembering the letters erased from the board. I love putting all the smart students in the classroom and the teacher on one team and the rest of the class on the other team. Usually, the not-so-bright team wins and it helps build their confidence.
As far as other subjects, when I was teaching ES, I used to try and connect each class to the prior one. No big explosive new idea there but I found this to be the best way for the students to review what was taught in the prior class while at the same time building on what is currently being taught. For example, if I taught colors in the prior class and was teaching animals in the current one, the animal would never be 'dog', but rather a 'blue dog' or a 'yellow cat'. This isn't the greatest of examples but my students are pulling me to class.