wemo plug with an IR heater plugged in sitting in the garage facing my home gym so i can get the barbell warmed up before i go out in 10 F weather to lift
a number of lifx wifi lights (no hub required) that will do any color + IR
ibaby monitor with night vision, temp/humidity/VOC sensors, etc.
soil moisture sensors + automated sprinkler system that i can control via web interface or API calls I built myself
a number of docker containers running designed by me, one for example watches the network for IIRC ARP packets from those amazon clicker things, one of which i used months ago to mark when our baby started or stopped drinking a bottle and then i could pull up a graph later
long term i plan to have sensors for all circuits in the house to monitor electricity use, primarily so when my wife says "your computer is on too much" i can point out how very little power computers use compared to refrigerators and shit
Edit: also alexa with some custom apps i wrote to help me cook hands free using recipes, a Zipp Mini smart speaker that I have some code on my network running to stream white noise to when I put the baby down for a nap, i think some other things
I basically dick around coming up with Doc Brown bullshit in my copious free time