Bank Holiday Blues

I haven't posted for a couple of days due to going down to Norfolk to stay with my parents. It would appear the everyone experienced a bit of a wash out this bank holiday (except for the Lake District I have read). Norfolk is definitely an outdoor county; there is very little to do there when it's raining, as we discovered to our cost.
My Mum had plans for my wife and I to take her to a local craft fair, which apparently was flooded out. My Dad beat a hasty retreat to the pub; had we not been enduring the 3 and half hour drive home I would have happily joined him. We, instead, went to a local garden centre; which as garden centres go was rather impressive. As well as a well stocked plant section, they had various outlets within the site (craft shops, cook shops, aquatics, the list goes on), unfortunately to access these you had to leave the overhead protection, so we still got rather wet.
If anyone does have any suggestions for things to do in North Norfolk on a rainy day, please let me know. My family have been living there for over 12 years and still have trouble thinking of things that don't involve shopping or alcohol (which is fine unless you are skint or driving!)!