Hydrophonic farming at home. You can play with sensors (acidity, humidity etc), LED lighting (frequencies, intensity, etc), vision processing (maybe throw in some AI buzzword here) to keep track of your plants and do some decision making.
The increased speed hydroponic plants grow at compared to plants in soil is what really makes it exciting for me. A plant in my basic countertop "indoor garden" unit is growing 10x as fast as a cutting of the same plant sitting in my windowsill.
Bonus: You get to eat the stuff you grow :)