Rainy week in North Devon

[roadtripper]

Any ideas what we can do with two toddlers (3 and 1) for a whole week in North Devon as it's set to rain heavily every day. Eek!

We're staying in a very small flat so staying in not an option.

Watermouth Castle - you spend a couple of hours going around the inside, but take an anorak for the outside bit - it's worth it.