If by chance you have some sort of mental disorder, BINGO. Your out of there.
They will not allow anyone to sit for jury duty that has a mind altering problem.
Just tell them you can't concentrate for long periods of time and you'll get of.
Tell them you have ADHD and watch them call you a cab quick smart.

I have done this and got out of jury duty myself, guaranteed to work.

Even if you haven't got ADHD it doesn't matter, I bet you can't concentrate on anything but kiting anyway.

There you go, you have a concentration problem.
So it wouldn't be like your lying to them or anything.

Good luck.