A small ruby app that prints a multiplication table of prime numbers.
It uses a simplistic incremental Sieve of Eratosthenes algorithm to find primes based on this [academic paper].
I build and deploy my gems using Snap:
Instructions
gem install primetable
primetable 10
This will print the first 10 prime numbers. You can try raising that number and seeing how far you can go.
Interesting Prime Number Resources
[Visualization of primes on the number line] (http://www.fastcodesign.com/1670397/infographic-visualizing-prime-numbers-for-people-who-suck-at-math)
Great Internet Mersenne Prime Search - use your spare CPU cycles to find the biggest primes