Part of the job requirements of a software developer (you'll find this is most any company) is the "on-call" shift. Each team member has a pager, and rotates weeks to serve as the first contact for any issues that may be discovered during off-hours.

Also on the job description: Release night. That is, the evening when a new version is rolled out to the customer. Each team has a representative at the office to perform testing when the release hits. These are done on rotation, so each member usually only has one about once a year.

Tonight is my first turn as a release rep. Which means I'll be showing up at the office when most sane people are just leaving, and I'll likely be leaving around midnight or so. I think I'll take notes on what it's like being in the office at that time, it could make for an interesting story at some point.

Thankfully they're providing food, and it sounds like the atmosphere is pretty light-hearted. I joked about bringing my DS to squeeze in a few rounds of Mario Kart. I hear the office has WiFi available...