You really do have to listen to them to get the full effect, but here are some of the lyrics that particularly made me laugh. First of all, for sheer simplicity, we have the chorus to "Stick it to Dolores":
Oh my god, you look like a frog [4x]
Umbridge, you're going down [4x]
Then the awkwardly-unmusical-lyrics award goes to "Wizard Chess", which is about Christmas activities and presents:
I got a mysterious gift from my dead dad
It was an invisibility cloak -- how rad
Oh, oh, oh-oh-oh
We'll spend our Christmas being invisible
Oh, oh, oh-oh-oh
We'll be invisible this Christmas
"The Human Hosepipe" was probably the one that made me laugh the most, though. Selected excerpts:
So we sat there with all the couples kissing
and soon things began deteriorating
and you began turning into the human hosepipe
...
[chorus:]
Cho Chang, what have I done?
I don't care where you and Cedric were snogging
Cho Chang, what have I done?
I just want to replay this Valentine's day.
...
Well, maybe I shouldn't have mentioned Hermione
And maybe you shouldn't have brought up Cedric Diggory
Because I'd rather not talk about your dead ex-boyfriends over coffee
My goodness, that was hilarious. Musical quality regardless, props to these guys for starting the band and making me laugh.