Woah... today, after our volleyball game, my friend came up to me and told me the EXACT same joke!

Here's another one he said:

So, two hydrogen atoms walk into a bar.
The first atom goes, "Hey, I think I lost an electron."
The second one says, "Are you sure?"
Then the first one goes, "YEAH! I'm positive!"

The sad thing is, is that I actually giggled. :P