I spent the last six days in Montreal attending the DrupalCamp Montreal and it's associated i18n code sprint. I took a few things away from the Camp itself, including a few nice ways of organizing the Camp. However, what I enjoyed the most, and what the organizers said was the most rewarding part for them, was the i18n coding sprint that happened a few days before the Camp.
They were able to book a room at a coworking facility downtown, and we spent Wednesday-Friday working on the D8MI and localization bugs in Drupal 7/8. They were able to get Gábor Hojtsy (D8MI lead and Drupal 6's maintainer) and Angie 'Webchick' Byron (Drupal 7's co-maintainer) to fly in and help out. The whole experience was a fantastic way to welcome people into the community, and had work to be done by contributors of all experience levels.
I learned more, met more people, and had the most fun during the sprint than I did during any camp. I'd love to be able to do something like this at DrupalCampTO this year. I'd recommend that we look into a few of the Drupal Core Initiatives, find one that we would like and try to get a three-day sprint going throughout our Camp this year.