wait two days before pitching yeast.....?

Saturday morning, today is brew day, I got the 33 lbs of grain for this 70 liter batch of Hefeweizen, plenty of propane for the burner, nice blue skies, the birds are singing.. Ideal conditions for brewin' in the yard this afternoon. However my yeast starter seems to have very little activity, it should be going mad by now.. the beer store is closed till monday, maybe I'll need new yeast, not sure how viable my starter is. You guys see a problem if I brew and fill the three carboys and let them hang out in my fermentation room until Monday when I can pitch yeast?

I would pitch the yeast anyways. Since it is in a carboy you should be able to see if fermentation starts between now and Monday.

Good luck with the brew

My yeast starters tend not to have much activity. All you're looking for is yeast growth, not necessarily high krausen. As long as you made the correct sized starter, you should be fine.