This was only a few blocks from Fenway (in The Fens). This was taken right before New Years. What are the red things growing on this?
Elegant Maple in Boston ID Please
I presume it's A. rubrum but of course others will confirm or refute.
Look like juicy buds getting ready.
Agree with Wee - most likely Red Maple (Acer rubrum) though Silver Maple (Acer saccharinum) will be similar. "Juicy buds" are this spring's flowers, which are among earliest shade trees (along with Elms) to bloom.
Differences are best noted when in leaf, but Silver Maple is often a more vigorous grower so will typically have longer twig extensions annually. Collect a thousand dormant twigs of each to compare flower buds in color, and you might discern a difference there too.
The leaves look quite deeply lobed - I'm going to go for the hybrid between the two Acer × freemanii. And yep, with flower buds.