Using a binary editing tool, sound software, and the courage to add a programmable ROM disk to your classic Mac, you can change the bootup sound (along with other tweaks) to whatever you want. If you have a Mac Plus, 128K, 512K, or 512Ke laying around this might be a fun project kit to experiment with.
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.