Some enlist as graphics or sound "floaters," lending their skills to a number of different teams, who sign up for their services on a waiting list.
While the majority of participants attend the event in person, recent jams have accommodated virtual jammers, due to space limitations and geographical distance.
From the official kick-off Friday evening, jammers have 48 hours to complete their games before displaying them in an informal Sunday night showcase at the event's close.
Scheduling allows jammers to fine-tune their games before presenting them to consumers, rather than creators, and it's usually held at a bar or pub in downtown Toronto.
The event was first suggested by Nelson Yu, a developer-turned-writer, in the IGDA community boards as a way to get more local game development, in an attempt to retain talent.