Speedrunners is a crazy multiplayer game, kind of a 2d platformer racing game. Imagine Super mario Cart, on foot, basically. There are traps on the map, you can use grapling hooks like spider man, and also, there are power ups, to really screw with your opponents.
I tried this with 2 of my buddies, and it was always a blast. The game is super fun, but a little demanding. Everything happens really really fast, and requires a lot of concentration from the player, so we only ever lasted for a couple of hours.
Perfect for a casual multiplayer party for the weekdays.
Also, some of the characters are hilariously ludicrous, but you have to see that for yourself. If you buy it make sure, to have at least one friend to play it with you. The online players will leave you in the dust like you were actually in a mario cart race on foot.