The last time we saw Stephen Day play a leading role was as Albin in the Arvada Center's The Birdcage some years back, when he was a fussy, silly delight. For the most part, he shows up in supporting though significant roles, as he did this year in A Christmas Carol: The Musical, also at the Arvada Center. And whenever he does, he adds warmth, assurance and a rich, strong baritone to the proceedings. As the Spirit of Christmas Past, he evoked every nostalgic, Dickensian thought you've ever had about the meaning of the season.