I think the coolest all-nighter I can remember is when me and one of my best friends were still in school. We were up all night figuring out what to make. At the time we played a little browser click game, so we came up with the idea of creating a bot for it.

We're both PHP developers, but we figured that wouldn't be an appropriate language to write a bot in. So we went for C#. Both of us never worked with it.

At the end of the night we built a fully functioning bot, that could continue playing the game when we were at school. It could do all our manual tasks and could even decode Captchas with the Google OCR package.

That night was productive.