At work there are a group of people that I have hung out with before. I can get a long with them in terms of small talk but that's about as far as it goes.

Recently they've been bugging me to go out with them for drinks/go round to their houses to hang out (bit forward?!)/ go to (shit) gigs with them etc etc

Besides the fact I have no money, I really don't want to hang out with them because I have absolutely nothing in common with them besides the fact that we work together.

The "I have no money" excuse will become redundant as of next friday and I can only be "too tired" for so long.

I can't be rude to them because I work directly with them 5 days a week.

WHAT DO I DO!?