Juice, from Boldport, is a solder-yourself battery replacement kit for use in prototyping and when you're out of battery juice.
It comes as a single panel that breaks out to six assembled batteries (two AAs, two AAAs, one CR2032, and one A23). The main board can be configured to provide three fixed voltages (1.5V, 3V, or 4.5V) or an adjustable voltage output.
The kit comes with a cardboard enclosure that can be cut, folded, and glued to create a lovely tuck-box for storing the assembled pieces.
Note: requires surface-mount and through-hole soldering!
Juice was project #12 of the Boldport Club.