Here's a logic problem for you to dwell on please don't post solutions for a few hours after this post to give everyone a chance to work it.

What you have:
12 cannon balls. A scale that measures 1 side vs the other (no numbers just the left side is heavyer or the right side is heavyer)

The Problem: 1 of the cannon balls is different (heavyer or lighter), you need to determine which cannon ball is different you only get 3 weighings to figure this out.
You don't know if it's heavyer or lighter.

also: if you like this problem I can post more at later dates so send me feedback.