Like a lot of people one of the first things I did with my Arduino was use it control an 8x8 LED Matrix and then get it to do fun things like scrolling messages and making little games. It's amazing what you can do inn 8x8.
Arduino Scrolling Message changed using Serial Monitor
Arduino 8x8 LED Racing Game
But going beyond 8x8 is not as easy as it seems due to trying to get the boards aligned and also just the sheer number of wires needed to connect all the driver ICs. From the video above for the Race Game you see there are a lot of wires just for an 8x8 if using a 74HC595 .
On one of my semi-regular trawl of eBay I came across the following.
It's 4 separate 8x8 LED modules with the MAX7219 driver IC included. No great shakes there as these are all over eBay and anywhere else you want to buy electronics bits.
The difference is the last word in the description 'Cascade' In the images and short video at the link they are shown in an 16x16 arrangement and if you look closely at the boards there are extra headers in each corner to facilitate the cascading.
Of course I had to buy a set which I'm waiting to be delivered. Slow boat from China. Could be a fun March when it arrives.