CPU Intensive Calculation Examples?

Question

I need a few easily implementable single cpu and memory intensive calculations that I can write in java for a test thread scheduler.

They should be slightly time con

Answer 1

1. Official RSA Challenge
2. Unofficial RSA Challenge - Grab some ciphertext that you want to read in plaintext. Let the computer at it. If u use a randomized algorithm, there is a small but non-zero chance that u will succeed.