One of the best games from the Cyberpunk Jam last month is online as a browser game, and you can play it now.
NeuroIDE demands (demands!) that you connect A sockets to C sockets, using the appropriate B. That involves combining numbers in different ways to achieve the correct results, using different mathematical signs. Once you've got that down, it'll show you how you're wrong, because your solution needs to apply to multiple dimensions, not just the one.
It's good for a small session, and won't tax your brain a crazy amount. Just the right level for the end of the day. You can play it here.
In fact, a lot of the games are playable, so why not check them out too?