I once had to learn 35 songs in an afternoon for a dep gig. I then drove 100 miles to the gig to find out I'd left all my notes in the rehearsal room [b][size=6]DUH!!![/size][/b]. The singer Neil, amazingly, managed to write out all the chords plus lyrics, in the 15 mins before the gig for about 30 songs from memory. And thankfully the gig went ok with no major fluffs.
So my brain capacity is miniscule..............but his must be like a small planet!