There's a lot of wisdom at The Quotations Page.
You can pick almost any page, at random, and find a doozy.
One good place to start is with Einstein.
I found this there:
"Put your hand on a stove for a minute and it seems like an hour. Sit with that special girl for an hour and it seems like a minute. That's relativity."
"You see, wire telegraph is a kind of a very, very long cat. You pull his tail in New York and his head is meowing in Los Angeles. Do you understand this? And radio operates exactly the same way: you send signals here, they receive them there. The only difference is that there is no cat."
But these two, taken together, are my favorites:
"Only two things are infinite, the universe and human stupidity, and I'm not sure about the former."
"I know not with what weapons World War III will be fought, but World War IV will be fought with sticks and stones."