Think of a device and build it yourself, with the Raspberry Pi 3 Model B motherboard. Connect a monitor, a mouse, and a keyboard, download the software and install it via an SD card. The graphics chip and the Broadcom BCM2837 processor make the Pi 3 powerful enough to turn it into a credit card-sized media player, for example. Connect the model to your TV via an HDMI cable, and stream videos at high resolution. Connect a touchscreen to the board, and turn it into a smartphone, robot, or controller. Think of smart applications and execute them via IFTTT or connect sensors, and build your own weather station or smart thermostat. Or recreate existing designs.
Download the required software and put it on a microSD card.