I would probably keep schtum too.
I would make anonymous donations to a couple of local projects that I am involved with, we are trying to raise money to repair the village hall and build a new nursery school. Between them those projects need about £250,000, it would be nice to be able to top up their fundraising so that the projects could go ahead now. I would also give money to things that my children use, like the school, the local park, the village football club etc.
I would buy a bigger house, but nothing too flashy (the sort of climb up the property ladder that could be explained away as an inheritance from great aunt Maude). I would also buy my mum a house more suitable for her (again, could be explained as an inheritance).
I'm not sure whether I would carry on working as I am involved with a lot of voluntary activities which would TBH keep me busy. But I know DH would carry on (he might retire earlier though).
We would have slightly nicer holidays, but again nothing hugely flashy.
A lot of money would be put away for when the DC are older and when we retire. It would be nice not to have to worry about the future.
I am probably incredibly boring though!