[Devils'Advocate]

I am having a contest for an audience that has a varied ethnic background... for most english is a second language. So if I gave word puzzles, those that do have english as their first language would have the advantage, which I am trying to avoid.

So the puzzles I'm thinking of are things like sequence puzzles;
23, 45, 89, 177, __
1, 3, 4, 7, 11, 18, __
7, 5, 8, 4, 9, 3, __
1, 2, 6, 24, 120, __

Math puzzles:
http://www.freeprintable.com/customi...t.html?id=2381

Maze puzzles:
http://www.freeprintable.com/customi...t.html?id=2291

Or logic puzzles:
http://www.smart-kit.com/s813/balanc...icture-puzzle/

Any other ideas?

Thanks for any suggestions!