What do you tell people when you have to take a piss?

[superchunk]

I have to go to the bathroom
excuse me
i have to drain the main vein
i have to download some data
gotta pee
gotta wiz
i have to drop off a few friends at the pool
i have to go potty (you can tell i have kids)
hit the head
gotta tinkle
oh, my bladder, be right back