This is one I see all over the place, especially on Facebook. It's pretty self explanatory I think. Simple and funny.
sin(x) doesn't quite work like that... Extra points for creativity though maybe? And they are right, six does equal 6.
This is one to hurt your head. I've not actually worked out where the contradiction actually comes into it. It's too late for that right now... (I'm very tired ok!) This is exactly the sort of thing that makes my sister hate maths. She still can't convince me though :)
Four pictures today, you lucky things! This one a friend sent to me. I didn't actually know that one Newton per square metre is a Pascal, but I think you get the jist of the joke anyway (well, I did). It made me giggle, so I thought I'd share it.