There's the museum and Oliver Cromwell's house. Depending on the day and the visitors, it's also fun to take people to the market, or turn them loose in the charity shops or Toppings. And I think I'd also consider day trips to Cambridge - maybe Bury St Edmunds or even Norwich, too.

The last time we had people staying in the house, I was still very tired after Covid and mostly had to let them amuse themselves. They went to Aldi and bought an absolute shedload of hot cross buns. So there you go.