Hi, all.
Thanks for coming to the Raspberry Pi evening! My plan was to talk with people and have then talk to each other far more than talk at them (I likely do too much of that in my job as a lecturer!) so it's great that you made this work.
There are lots of R∏ resources online but one I want to mention concerns the hardware stuff I demonstrated. This is a good place to start
http://elinux.org/Rpi_Low-level_peripherals#GPIO_hardware_hacking
and the diagrams under "P1 Header Pinout" are very useful. That page includes sample code in many programming languages.
Cheers!