I know they were asleep, but...they were your guests and you left your own home to go where it was more fun for you? They may never have known what you were doing but maybe this year you can try to be more accommodating and involve them more, rather than leaving if they don't celebrate in the way you prefer.
Plan activities-- don't let everyone get into sit-down mode or they'll fall asleep. You'll need your husband's backing, though. Ensure that as soon as the holiday meal is done, everyone goes for a walk, around the block at the least, and yes, even in the snow, unless it's unsafe and icy. Get out a game and have it already set up and ready before anyone even arrives; talk up the game during dinner.
And most of all-- if the in-laws just check out and still don't participate, enjoy it with your husband and kids. Not all families are the same, and it sounds like you'd like your in-laws to be as fun and active as your own immediate family; you can try to goose things up for a more active holiday but don't be crushed or angry or take it personally if they don't go for it; at least you will have tried and you can go on and celebrate around them as they sleep. They are who they are and they may see your family's dancing, singing and games as too much, while your family would see their relaxation as too lazy. No one's right or wrong -- you just find it too quiet. But for one day you can deal with them, right? Because it's about accommodating your husband's family that raised him, not just about having the fun you're used to having. You can do both if you're willing to invite them to participate but also willing to forge ahead with the games etc. if they don't participate. Your kids will learn from this to be good hosts, to invite others to take part, and to have fun on their own with their family if others don't take part.
One other thought -- are your MIL and FIL older folks? Maybe not very fit? They may actually not have much energy especially after a heavy meal, or they may fall asleep in front of the TV at home on a regular day, not just at your house on a holiday. I'd cut them extra slack if they are older, set in their ways, or possibly not in great shape.