When I worked in Switzerland, every Friday when I was not travelling, I met my husband for dinner in a restaurant which was quite close to my work. I was often very late (!) but they got to know us well and used to keep the table for us and he brought a book. It was a nice routine (even though I was late - indeed I would argue that was part of the routine
). I think with stuff like this when you are working really hard a bit of routine helps, otherwise the lure of the sofa, TV and pizza is too strong to resist. Also, I find that if I go home first after a long and busy week I just cannot get motivated to go out again.