IT gives plenty of suggestions on preventing data loss due to computer crashes during exams, but this year my friends have suffered from a different problem: malfunctioning laptop chargers. If you are working on mission critical material, you need to have backups. Dropbox is great for protecting against losing your latest changes and for making it easy to continue your work on a different computer. But, if you don't have access to another computer, you need a plan B.
With common laptops, like current generation Macs or Thinkpads, it's easy to borrow chargers. But, if you have a more obscure adaptor you should consider investing in a backup charger so you don't end up in this predicament.
Remember that Murphy's Law dictates that your charger will break at the worst possible time, when friends are unavailable and stores are closed.