well, most of their songs are in drop C or CBCFGC, but some of the acoustic intros (a la Question!) is in standard. what you could do is just go to Drop D, which is just the low E string tuned down to D. it's the easiest to do probably
Epiphone G-400
Yamaha Pacifica (Mod on hold due to procrastination)
Rocktron Banshee
Marshall 10CD

Quote by geetarguy13

I've never smoked before but it looks like fun.
There is none. Drop tune to CGCFAD or C#G#C#F#A#D#.

EDIT: ^ I don't think that they made songs in C standard.