Good question.
Depends on free time but (in no particular order).
1. Design case for my PI with 7inch touchscreen and IQAudio DAC+ board and print it on my 3D printer.
2. Sort out a better arm pod for the wooden 12 inch arm
3. Complete a Lenco GL75/GL78 TT build I started 10+ years ago.
4. Build a new preamp using some components I have lying around.
5. Build another TT using the spare Orbe platter I have lying around
6. Rebuild a pair of Heybrook HB1's I have stashed in the garage.
7. Design a music centre using spare PI and Lenco GL75 (for fun...)
8. Finish off the tangential tone arm I helped a bit with on the DIY forum
9. Using some spare valve poweramps I built in the early 90's see if I can build a nice pair of EL34 monoblocks
10. Finish off the rebuild of my 1972 VW camper van.
I wonder how many of the above will get done this year