Here are some cheers from the University of Waterloo Math orientation (which I went through 4 years ago). These include such classics as Math Rocks, The Biggest Tie, How's the Tie, and Water Water Water. I'm not sure why, but my personal favorite is The Biggest Tie.

Math Rocks

M-A
M-A-T
M-A-T-H
Math Rocks!

Say it loud
Say it big
Let it boil in your blood, feel it zag as you zig
We survive
All the knocks
We have pride when we cheer and we think Math Rocks!

One group chants the first verse while the other group chants the second verse, at the same time. The chants should converge on the phrase "Math Rocks!".

The Biggest Tie

The biggest tie
I ever saw
Was hanging from
The MC wall

I looked at it
And then I knew
I wanted to be
A Mathie too

I stole the tie
It made me laugh
Because it's true
That I love Math

And so began
My new journey
To be part of
Math faculty

My school is sweet
SWEET LIKE A FOX!
Because I know
UW Math Rocks

Sung to the tune and style of The Littlest Worm, The Princess Pat, or I Met a Bear.

Water Water Water

Water water water!
Loo loo loo!
Water water water!
Loo loo loo!
Water!
Loo!
Water!
Loo!
Water water water!
Loo loo loo!

One group (typically the orientation leaders) starts the cheer by yelling "Water water water!". The other group then replies with "Loo loo loo!". It continues in this fashion until the end of the cheer.

There are more Math cheers in the Math Handbook Math Orientation 2008 guide.