If you have an interest in aircraft then a cheap and easy way to receive details of aircraft near to you is using a cheap USB TV tuner as a software defined radio to decode aircraft radar transponder transmissions. Modern transponders can transmit more than just a squawk code and altitude allowing you to see their identity, position, speed and direction, and a Raspberry Pi is cheap enough to dedicate to the task. Tuners can be had from eBay for less than £10.
Make a robot friend with Adafruit’s CRICKIT – A Creative Robotics & Interactive Construction Kit. It’s an add-on to our popular Circuit Playground Express, FEATHER and other platforms to make and program robots with CircuitPython, MakeCode, and Arduino. Start controlling motors, servos, solenoids. You also get signal pins, capacitive touch sensors, a NeoPixel driver and amplified speaker output. It complements & extends your boards so you can still use all the goodies on the microcontroller, now you have a robotics playground as well.