I found several printables for them to color including a "Viking Princess" for Elisabeth (well, that's what I called it to keep her interested).
I found several boat making activities. My guys still don't handle scissors so well so mommy ends up doing most of the cutting. I printed off some things for them to color while I cut out and put together this Viking Longship Project that I found on the Navan Education Center's website in Ireland. After stapling the cardboard pieces together and adding a mast, I brought out the acrylic paint for the kids to paint. We added the sail and the dragons head and voila!
There are lots of Viking related resources out there especially for older kids. For Kindergarten you kind of have to sift through and find what suits your kid's skills and interests.
NOVA has a quite a bit of information out there as well as this neat interactive where you can see what your name would look like in Runes.
The BBC has a great interactive website on Vikings.