Sessions are the times players come together to play D&D. Sessions can be hold online or in real life, usually lasting between 1 to 3 hours. Sessions often happen on a weekly or bi-weekly basis. The whole continous story you and your party (group of players) play is called a campaign. Many campaigns last months or even years! If a group of players is meeting to run a one-session, self-contained story, this would be called a "one-shot." While the game is rule-heavy, there are plenty of chances to get creative and get silly. In the video, the characters are currently falling. One player summons Daern's Intsant Fortress, a cube that rapidly grows into a 20 feet wide and 30 feet high fortress with a ladder running on the side.