Using AOL to email OPORD's to the B Team because the SOCA wasn't working. Does that count?
My old Det SGT used some spare wire and a soldering iron to make a harness to power PRC-70's and PSC-3's from a HUMV battery. It seems the 24v current was excellent for those older radios and we didn't have to use our supply of 5590's.
A slinky as an antenna for a PRC-127. I've since used a slinky as a field expedient antenna for civvie radios to receive as well.
Before CamelBaks were the rage, we'd take surgical tubing and attach it to the NBC caps on our 2 Qt. canteens.
For batteries (I used this for R/C cars, but the principle is the same) you can build a dissipater from car tail lights and wire. Batteries have a memory, so you want to discharge them at the rate they are used. Tail lights are cheap and have the amperage drain needed.