TTRPGs like GURPS or OpenD6 for free group activities. All you need are pencil/paper/notes app and 3 6-sided dice, and you can roll them with an app or on plenty of webapps (dddice.com is a good one for shared gaming). A lot more to learn than playing cards or board games, but much more fun than a typical game night, something the group can talk about all week between sessions.