The Raspberry Pi is a fantastic basis for making your own electronics projects, but it's not always easy to connect exterior elements to it. If you want to play around with buttons, lights or triggers, the Prototyping Pi Plate from Adafruit makes that all easy to manage.
The plate has a large breadboard area, a section for breakout pins, and some space for non-GPIO wiring. Basically, it makes it a heck of a lot easier to instantly add in exterior components to the Raspberry Pi so you don't have to worry about soldering directly to the Pi itself. If you plan on using your Pi for anything that needs buttons or blinking lights, the Prototyping Plate makes it a lot simpler. You'll need to do some light soldering to put it together, but it's easy enough that novices should be able to handle it.
Adafruit Prototyping Pi Plate Kit [Adafruit]