Built myself a couple of things that were missing from my toolkit.
The AVR-based LC Meter by YO6PIR to ballpark hand-wound and unknown inductors.
Yes.. It's not the prettiest thing to behold in the cheapo electrical box enclosure I put it in, but it works. There's some drift that I'm not sure whether is inherent in the design or something I messed up but it still works well enough.
and the ESR Meter Project by VE7IT which will be very useful for random repairs.
(PCB shown incomplete and capacitor soldered in with wrong polarity)
I've since marked a few values on the cover with a sharpie. About 80% of the scale is 0-10 Ohms which works out well enough since looking at ESR charts will tell us that almost every electrolytic should have an ESR well under 10 ohms (except low capacitance high-voltage ones). Most of the time a good cap will produce close to full deflection. (The one being measured in the picture is a 3.3uF 400V so It should still be in great condition at around 8 Ohms ESR.)