Jokes.

I will give a starting one:

Two scientists walked into a bar.
One said "I want some h2o."
The other one said "I want some water too. Hey, why did you say h2o? I mean, it is the combination for water and all but it does complicate things a little."
The first one sneered as his assassin plan failed.
h2o =  Water
h2o2 = Hydrogen peroxide
I made this from:
Two scientists walked into a bar.
One said "I want some h2o."
The other one said "I want some h2o, too.
The second one died.