Have you considered retro-gaming? If the laptop isn’t much older than 20 years it should probably manage to run dosbox, and with it you can get a ton of old IPX multiplayer titles running, for instance Warcraft: Orcs and Humans, Transport Tycoon, or Command and Conquer: Red Alert.

(Transport Tycoon also has an open source remake, OpenTTD, that can run on a potato. OpenTTD also runs in a browser, but afaik the browser-version is limited to single-player.)