Do you have weights or a treadmill? One of things my friends who work from home or have start up software companies really benefit from is being able to have a physical release after working on a computer for so long. Tony Robbins says that our physical state needs to match our mental state. Being able to work yourself up physically will make working a lot easier, because your physical stasis aligns with the intensity of a lot of the mental work.
At Naughty Dog and Microsoft here in LA they have a gym, a yoga studio, and resting space so that they can physically align with whatever kind of work they're doing.

I agree with competitive multiplayer games. Those are great fun ways to get people hyped. Things like Fifa are great and FPS games are really exciting when you know the people you play them with. Tekken is a great game for two people to take their day out on.

ONE LAST THING. TEA, a friend I made who works at Naughty Dogg as a higher up and he swears by tea, it's incredibly cultural, there are different blends for different moods. A lot of people get behind it as an alternative to coffee or magnesium, and as hobby learning about all the different types is fun. And when done well it can be a very communal experience with whoever is serving the tea almost as a bartender where he can give you a blend to feel focused, hyped, relaxed, or whatever you need to get your job done.

Hope I helped in some way :)