Have a look at the good things to see in London thread and pick some. Or go to your nearest train station, buy a ticket, get the next train that comes in (unless it's your usual commuter train) and get off wherever you fancy and just go for a wonder and explore. Take a book and walk to a nice pub or cafe. Have lots of lie ins. Visit someone you haven't seen for a while. Do some DIY or gardening. Erm i can't think of any more, just do what takes your fancy at the time. Have a good week.