One of the fun teaching methods I like to use is to teach concepts with either a song (to the tune of popular song) or a chant (just to a rhythm or beat).
While it always takes a few students a while to be comfortable with it, by the end of the year my students always say that is one thing they will remember about my class.
They come back to me the next year and tell me "I used 'such and such' chant to help me on my Calculus test!" or "I still remember those songs!" I have students email and Facebook me once they are in college saying how helpful the songs and chants still are.
The most important thing about using songs and chants is that they actually have to be content-based and not just "fun". The lyrics and words must be things that students need to know and remember, and learning them to a beat just makes them easier to recall.
The majority of the songs and chants are developed and written by me as I figure out things I know my students need to know but generally have trouble remembering. It takes some time to develop some of them and make sure they flow and are clear with the content they go over, but it is really fun and helps to create an engaging class environment.
Ones I never got around to recording while I was in the classroom :(
1. Infinity...parentheses [interval notation]
2. Parallel and Perpendicular slopes (chant)
3. Multiplying Fractions (chant)
4. Steps for simplifying rational expressions (Shake, Shake, Shake)
A few of my personal favorites: