[Halcyon]

3 weeks is indeed a nice amount of time off but think about things you've always wanted to do and never had time to do.

Catch up on sleep, maybe buy a new game if you are into gaming, go out to the cinema, go to town, browse the shops, go into the countryside and get some fresh air, tidy your house, watch TV, listen to music, go spend a day in London, learn something new you've never tried before, or just do nothing.......holidays are intended to relax so take it easy.
Maybe go out and meet some new people too...you could go go ice skating, take a train to another town and go discover a new place for the day, go take some photos if you enjoy photography, read a new book, go to see some sports games, go check out the other fast food stores and rate the competition between all of them, etc.

Lot's of possibilities.