Pretty medieval manuscript of the day is the Black Hours, one of a very few manuscripts on vellum that is dyed black. This image is of folios 18v and 19r shows Whitsun (also known as Pentecost).
For a digital exhibition, take a look at the Pierpont Morgan library website.
Image source: Free Christ Images website, and licensed for re-use with attribution.

(via t-s-k-b)