Being available for important things

It's always when I'm in the shower.  The kids' radar activates and tells them that now is the best time to ask Mom that really not-incredibly important question.

Let me set the stage:

Fan is blowing, shower is running, water is clogging my ears.

I hear indeterminate mumbling just outside the bathroom door.  Think Charlie Brown's teacher.

Me:  You know I can't hear you right?  If it's important come on in so I can hear you.

Door opens.

7 year-old boy: Mom, what's that thing you do for a hundred years?
Me, trying to make sense of what I think I just heard:  Wh-huh...What?
7 year-old boy:  That thing, that lasts a hundred years.  What's it called?
Me, wondering where this is going: A century?
7 year-old boy:  Oh yah. 

Click.

And he's gone.