Yes! I did two Tough Mudders this year and they were both awesome! I highly recommend it for everyone, honestly.
As you can tell by my weight, I'm not skinny or fit and I still had a GREAT time. There were people of all different sizes going at different paces and everyone was helping everyone else over the obstacles (even my fat butt).
I would definitely suggest trying to get in shape for this because I think it would've been more satisfying, but if you don't then it's not a deal-breaker. I had every intention of doing that, but was (and still am) the same as you in having trouble counting calories and exercising and I still had a blast. Seriously.
Edit: I wrote up a race report on my first TM in my blog here
, and have another blog post comparing Warrior Dash to Tough Mudder here
, so hopefully those help in getting a sense of what the "race" is like. I still haven't finished the second write-up, but I will get around to it sometime soon. I think.