One of the fun and cheap projects you can do is track all the aircraft that are flying around you. All commercial and some light aircraft are required to have an ADS-B transponder that sends out a radio signal on 1090MHz that contains their location, speed, etc. These signals can be received with one of these SDR dongles and decoded to display this information on your computer.
There is even a ready made piece of software called dump1090 (and many, many forks of it) that will also display this information on top of a google map.
Stop breadboarding and soldering – start making immediately! Adafruit’s Circuit Playground is jam-packed with LEDs, sensors, buttons, alligator clip pads and more. Build projects with Circuit Playground in a few minutes with the drag-and-drop MakeCode programming site, learn computer science using the CS Discoveries class on code.org, jump into CircuitPython to learn Python and hardware together, or even use Arduino IDE. Circuit Playground Express is the newest and best Circuit Playground board, with support for MakeCode, CircuitPython, and Arduino. It has a powerful processor, 10 NeoPixels, mini speaker, InfraRed receive and transmit, two buttons, a switch, 14 alligator clip pads, and lots of sensors: capacitive touch, IR proximity, temperature, light, motion and sound. A whole wide world of electronics and coding is waiting for you, and it fits in the palm of your hand.