Today I spent about half an hour burning bootloaders on AtMega328P ICs for DIY Arduino Kits.
It was fairly repetitive, but without Nick Gammon’s excellent bootloader burning program, it would have been lot more complicated. I downloaded the code and instead of having it ask for serial input, just gave it all the values required.
I used 2 of my DIY Arduinos connected with 6 jumper wires. For each AtMega328P, I first bent the pins inwards by pushing it against a table so that it fit in the IC socket. Then I put it in the IC socket, press the reset button on the other Arduino, and wait for the LEDs to stop flashing.
In about half an hour (while playing Chinese Checkers), I was able to burn the bootloader on around 80 AtMega328 ICs.