My sister Amy graduated from college this weekend. I'm so proud of her, you'd think I had something to do with this great accomplishment. But all I did, for the last four years, was watch in awe as she raced through college at top speed, collecting an amazing variety of experiences and accolades.

Oh, that's not quite right. On occasion, I also nagged her unmercifully to spend time with her family, most notably: me.

In spite of my (very expertly applied) nagging on the subject, it was only this weekend that I learned some Valuable Lessons* of my own about time spent with family.

Lesson one: if there at least two members of the smaller set around, I will never be able to call them by their names. I know who these kids are, of course. I adore each and every one of them, and I was thrilled to get to spend time with my nephews and niece. They are the Greatest Kids in the World -- a floating title that applies to every child in my loosely-defined family, either by birth or bonds of friendship.

But not once this weekend did I get any of their names right.

I know their names. I know their full names, birthdates, some of their likes and dislikes, and exactly where and to what degree each one is ticklish. I know things about these children that I consider to be among the most precious bits of information in my sometimes-spotty memory.

And as soon as two or more of them were in the same vicinity, I lost all ability to use any of that information. I called them interchangeably by the names of 'Honey', 'Sweetie', 'Darlin' ', 'Sugar', and 'Angel'. I did manage to apply the name 'Princess' to the correctly-gendered child, at least, but outside of that, I was hopeless.

It's really not surprising that my sisters don't send their kids to stay with me -- based on weekends like this, it would seem that I am too mis-informed to remember, from moment to moment, which one carries what name. And if I can't get that right, then clearly I can't be trusted with larger things, like making sure they get fed and don't play with the power tools.

Lesson two: time spent in the company of family doesn't obey the same laws of physics that apply to non-family time. I've never realized this before, but it's true -- this entire weekend seems to have taken place outside the normal flow of time. (Or maybe I spent too many hours watching and discussing Star Trek this weekend?)

They all arrived late on Friday. By the time we made it to the post-graduation lunch on Saturday, it felt like we'd all been hanging out together for at least a week (and not in a bad way!)

In spite of that feeling, Deb and her kids left, and there was this wrenching sense of, "But you just got here!". Other things disoriented me, too -- Doug went to a baseball game, and when he asked for directions to the Dell Diamond, I almost said, "But you know where it is -- you've been here long enough!" in spite of the fact that he doesn't even live in Texas at all, much less in Austin.

When Doug, and then Rachel and her family, and then Mom, left today, the house seemed too empty. It felt like we'd packed a month into 36 hours. It was hard to believe that it wasn't yet noon. In fact, I couldn't wrap my mind around the idea that it was only Sunday. The day after Graduation Saturday. Which was, in turn, the day after a completely normal Friday spent at work.

I spent the rest of the day looking anxiously at various clocks and calendars. Surely there was something wrong with the flow of time, that it felt like I hadn't been at work in a month? Surely some sort of hole opened in the time-space continuum, and we'd been sitting squarely in it for days, while only a few hours went by in the rest of the world -- right?

But after a nap, and a belated stab at the housekeeping chores, things seemed to go back to normal, time-wise. The regular flow of suburban life took over -- the yard to be mowed, the laundry to be done, the groceries to be bought, all that sort of thing.

But still...the house feels too quiet. And I worry that there will be cobwebs on my desk tomorrow.

Lesson three: any time there are three or more Star Trek geeks in the same room, someone will inevitably use the phrase 'space-time continuum' and all the geeks will nod knowledgeably, even though our total grasp of the concept comes from Star Trek itself.

Those same geeks will get into a pitched, but civilized, verbal battle over which captain was best. This intense conversation will drive all non-Trekkers out of the room; the Trekkers will not notice. The first person to bring up Captain April loses. (Sort of my own personal Godwin's Law.)

And worst of all, this discussion will mess with the head of at least one of the Trekkers, so that she spends the next week (or is it a months? a day? an eon?) convinced that she's actually fallen into some sort of hole in the space-time continuum.

* Oh, like you never watched The Brady Bunch. I swear, every episode contained its own little Valuable Lesson that was supposed to help good little Bradys -- and were there any other kind? -- grow up to be good big Bradys.