There's a game you can play for free online that's similar to Werewolf/Mafia. It's called Town of Salem. It's a lot of fun and can get pretty crazy at points. I know they were also planning on making it a card game, but I don't know if that's came out yet or if they're still working on it.
Both of those are by the same company, Rather Dashing Games. One of the creators used to be on the show Ghost Hunters, but now he makes board games. They're an awesome company that makes great games though, so you definitely should check them out! Both of the guys are super nice. I've met them a...
I love board games! I wish I got more opportunities to play them. Some of my favorites are:
Dwarven Miner
Four Taverns
Ticket to Ride
Munchkin
Settlers of Catan
Trivial Pursuit
Clue
There may be some that I'm forgetting about, but those are the main ones. I also love any type of trivia...