Do you have any poems you have memorized? Why did you memorize them - was it something in school that stuck with you?

Memorizing poetry has recently become a hobby of mine. I like it not only for the poetry, but because it gives me something to do in my "in-between" time on the subway, walking down to the convenience store, standing in line, etc. It's like carrying a free book of poetry everywhere I go. I've also found that repetition of the poems enhances my understanding of them over time, in ways I couldn't have guessed before. My favorite poets to memorize currently are e. e. cummings and Emily Dickinson.

Anyone else share this hobby? Suggestions on poems good for memorizing?