either a starter, or 'proof' the yeast a few hours in advance. If it doesn't proof, its dead. Game over man, game over!
if it did sit at 70F and didn't have any temperature extremes, its most likely still viable.
Primary: English Mild
On tap: Pale Ale, Lancelot's Wheat, English Brown Ale, Steam Beer, HoovNuts IPA
Bottled: MOAM, Braggot, Raspberry Melomel, Merlot, Apfelwein, Pyment, Sweet mead, Cabernet
Gal in 2009: 27, Gal in 2010: 34, Gal in 2011: 13, Gal in 2012: 10