I've made a 2L yeast starter (Wyeast 2633 Octoberfest) and placed in the fridge this morning. My original goal was to brew tonight but I may not be able to. Will the yeast colony still be good for a few days if it remains in fridge?
It should be fine if you store it in the fridge for up to 1-2 weeks. I have heard you could let it go longer but to be on the safe side I would use it sooner rather than later. If you do let it sit longer you could always decant the liquid and add more wort to get it going again.