What would be a good presentation for a college class covering Shakespeare's Sonnets 27 to 55?
Shakespeare's Sonnets 27 through 55 cover a lot of territory. One approach you could take for a presentation would be to compare the topics and related themes of the sonnets. For instance, Sonnet 27 opens a section of meditative, quiet sonnets that ends with Sonnet 30. Sonnet 27 tells of how the poet/speaker is weary in limb and dashes off to bed but once there is kept (one thinks pleasantly) awake by thoughts of the beloved.
As another instance of wide changes in topic and theme, Sonnet 42, the last of a trilogy, decries the pain of having been betrayed. It uses a bitter ironic twist in saying that while his friend betrays him to steal away his mistress, the friend does so only because the mistress is loved by the poet. In kind, the mistress suffers to accept the friend only because the poet calls him friend. Thus, with tongue-in-cheek ironic wit, the poet concludes that therefore he has lost neither friend nor mistress because both friend and mistress love the poet most of all--as they embrace each other for the sake of love of the poet.
Another example of topic and thematic changes is Sonnet 55 in which an oft repeated theme (Sonnets 18, 65, 123 etc.), borrowed and adapted from Horace, immortalizes the beloved in the sonnet; Horace immortalized a poet in a monument. This sonnet immortalizes the the beloved in a manner better than with stone "besmeer'd with sluttish time," and is thus a "living record" of the beloveds memory.
[For more information and analysis, see Shakespeare's Sonnets, by Oxquarry Books Ltd, from which this answer is drawn.]