Raspberry Pi – first impressions

I finally ordered myself a Raspberry Pi 2 model B.  I have friends who already have them and the simple platform for programming and experimenting with electronics.  I know nearly nothing about electrical engineering, so I have a bunch to learn.  My kids took to it right away, and the 9 year old, who I’d shown Scratch before, started programming right off.   We ran Minecraft and set up the wireless dongle that came with the bundle I bought off  Amazon.  We found Wolfram and Mathematica already installed, but I don’t know much about either.
I’m waiting for the LEDs and buttons I ordered to try playing with the GPIO.