I've been getting into Doppelkopf! It's a trick-taking game with tons of rules and variations on those rules and a kinda weird ordering for the trump cards, but it's quite fun. My favorite thing opposed to other trick-taking games is that you start each round but don't necessarily know who of the other 3 players is on your team. So each round can end up requiring a different strategy!
It's pretty complex, but my gf's mom has been teaching the two of us and her sister, so it's a bit less overwhelming. Tons of people in my department play at university, so I'll finally be able to drop in and play a few rounds with them as study breaks :D