Trelleborg is the site of an old Viking fortress (dated to about 980 AD) which covers about 15 acres and possibly housed 500-800 Vikings, just outside of Slagelse, Denmark. Although the site had been known about for ages, excavation only really began in 1933 when a motorcycle club began making plans to turn the circular rampart into a raceway. There is a museum with artifacts and skeletons, a gift shop, and games and activities for children. The large, open, grassy fields and picnic tables also make it a great place to take the kids.
If interested, you can read more about it here, and the museum's website is here. One thing I will tell you, though, that I haven't seen mentioned, is there were quite a lot of sheep roaming the grounds. When there are quite a lot of sheep, there is quite a lot of sheep poo. So if you go through that little wooden gate any time soon, be prepared to tip-toe and dodge your way through with e v e r y s t e p . Also, they don't want you to try to pet the sheep - they run away anyway if you get anywhere near.
old Viking games
site of the fortress (mind your step)
learning to shoot like a Viking
a reconstruction of one of the long houses (now thought to be not quite accurate, but still pretty cool)
we happily discovered Ben 10 ice cream in the gift shop
I wore my Stuart Weitzman Donuts because of course I had to have my only gladiators along for a trip that included Rome, and they are insanely comforable. Luckily, they also clean up quite easily with Lysol wipes.