You can find the challenges of the month in the Small Basic forums. Here are the October challenges.

For the September challenge, the Wave Challenge was offered in the Physics Challenge section:

Create a program to simulate waves.  Quite a general challenge so tackle it how you want - could be a water wave (2D) or a wave along a string (1D).

Note that there's a Physics Challenge each month.

Here is Noah's review of the Wave Challenge:

"After I finished looking at [the September] challenges, when I saw the Wave Challenge, I was very excited to see what some people would come up with. My personal wave challenge favorite is NaochanON's response. The waves are very nice, and the wave loading sequence. My only complaint was that the boat sometimes did not keep up with the wave. Overall... 9/10. Great job!

Here is Naochan's Wave Simulation:

  

See the simulation in action here.

And then here is JKrueg's version:


Interact with it here. You can tap Up on the arrow keys for a bigger wave and Down for a smaller wave.

Enjoy!

   - Tall Basic Ed