Do teachers get smarter in the summer?

I ponder because our mostly Rio teacher Sac Brew trivia team, currently named "Wipe the Klingons Off Uranus. Please!", often does better during the summer. And I nailed today's NPR Sunday Puzzle Listener Challenge fairly quickly. I usually don't even try. I enjoy playing along with the on-air puzzle, but the listener challenges go right through me.

I know that when school is on, it consumes my focus to the exclusion of nearly anything else. And if you know me, that explains a lot of things (sadly). So when Alice Cooper's "School's Out" rips through campus on the last day of school, it's as if a burden has been lifted and I can finally slow down my curriculum-development activities to a civilized pace.

Anyway, here's the challenge. Submit your answer via the link above.

A calculator displays a five-digit number. The first four digits are 8735. These digits form a logical sequence. What is the fifth number in the series?

UPDATE: Car Talk's Puzzler for the week of June 9 didn't fare any better against my "First Sunday of Summer" mental agility.

And if you didn't click that Alice Cooper link, you're seriously missing out.