Was set to brew tonight, starters are all set to go. Now due to unforeseen circumstances I won't be able to brew until next weekend. Will my starter hold up until then?
Assuming it's an ale yeast, you're best to put it in the fridge and keep it below 50F. Let the yeast go dormant. Then warm it up to room temp before you pitch. If you don't have an airlock in, you probably want to put one in now. This should help keep the yeast healthy and free from contamination.
Just put it in the fridge and let the yeast floc; pour off the liquid on brew day; then let it warm up and pitch it like a tube of white labs after that.