Getting students to solve problems is what Computer Science is all about!
I do like to set students difficult (challenging) puzzles to see if they can work out a solution.
This puzzle is one that I just came across and it took me about 5-10 minutes to solve it so I would think that students should be able to solve it too within a similar timeframe.
The objective is to arrange the pegs (numbers 1-8) such that no consecutive number touches on any connecting line.
For example number 1 cannot connect with number 2; number 2 cannot connect with 3 or 1; number 5 cannot connect with 4 or 6; etc.
The board layout is on the right:
Apparently there are actually four solutions but each one of those is a mirror of the one true solution.
Contact me for my solution if you need it by either emailing me, tweeting me, or leaving a comment on this blogpost. A little bit of logical thinking should enable most people to solve this puzzle quite quickly