Here are some links to past papers and mark schemes for some of the more common exam boards:

Edexcel Maths IGCSE old spec (4MA0)

Edexcel Maths A level old spec (9371)

Here is a selection of YouTube clips for your interest and amusement:

Zeno's paradox of Achilles and the tortoise

The famous Monty Hall problem - could you win the car?

Richard Feynman on knowing something